/**
 * MIT License
 * 
 * Copyright (c) 2014-present, Lee Byron and other contributors.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
  typeof define === 'function' && define.amd ? define(['exports'], factory) :
  (global = typeof globalThis !== 'undefined' ? globalThis : global || self, factory(global.Immutable = {}));
}(this, (function (exports) { 'use strict';

  var DELETE = 'delete';

  // Constants describing the size of trie nodes.
  var SHIFT = 5; // Resulted in best performance after ______?
  var SIZE = 1 << SHIFT;
  var MASK = SIZE - 1;

  // A consistent shared value representing "not set" which equals nothing other
  // than itself, and nothing that could be provided externally.
  var NOT_SET = {};

  // Boolean references, Rough equivalent of `bool &`.
  function MakeRef() {
    return { value: false };
  }

  function SetRef(ref) {
    if (ref) {
      ref.value = true;
    }
  }

  // A function which returns a value representing an "owner" for transient writes
  // to tries. The return value will only ever equal itself, and will not equal
  // the return of any subsequent call of this function.
  function OwnerID() {}

  function ensureSize(iter) {
    if (iter.size === undefined) {
      iter.size = iter.__iterate(returnTrue);
    }
    return iter.size;
  }

  function wrapIndex(iter, index) {
    // This implements "is array index" which the ECMAString spec defines as:
    //
    //     A String property name P is an array index if and only if
    //     ToString(ToUint32(P)) is equal to P and ToUint32(P) is not equal
    //     to 2^32−1.
    //
    // http://www.ecma-international.org/ecma-262/6.0/#sec-array-exotic-objects
    if (typeof index !== 'number') {
      var uint32Index = index >>> 0; // N >>> 0 is shorthand for ToUint32
      if ('' + uint32Index !== index || uint32Index === 4294967295) {
        return NaN;
      }
      index = uint32Index;
    }
    return index < 0 ? ensureSize(iter) + index : index;
  }

  function returnTrue() {
    return true;
  }

  function wholeSlice(begin, end, size) {
    return (
      ((begin === 0 && !isNeg(begin)) ||
        (size !== undefined && begin <= -size)) &&
      (end === undefined || (size !== undefined && end >= size))
    );
  }

  function resolveBegin(begin, size) {
    return resolveIndex(begin, size, 0);
  }

  function resolveEnd(end, size) {
    return resolveIndex(end, size, size);
  }

  function resolveIndex(index, size, defaultIndex) {
    // Sanitize indices using this shorthand for ToInt32(argument)
    // http://www.ecma-international.org/ecma-262/6.0/#sec-toint32
    return index === undefined
      ? defaultIndex
      : isNeg(index)
      ? size === Infinity
        ? size
        : Math.max(0, size + index) | 0
      : size === undefined || size === index
      ? index
      : Math.min(size, index) | 0;
  }

  function isNeg(value) {
    // Account for -0 which is negative, but not less than 0.
    return value < 0 || (value === 0 && 1 / value === -Infinity);
  }

  var IS_COLLECTION_SYMBOL = '@@__IMMUTABLE_ITERABLE__@@';

  function isCollection(maybeCollection) {
    return Boolean(maybeCollection && maybeCollection[IS_COLLECTION_SYMBOL]);
  }

  var IS_KEYED_SYMBOL = '@@__IMMUTABLE_KEYED__@@';

  function isKeyed(maybeKeyed) {
    return Boolean(maybeKeyed && maybeKeyed[IS_KEYED_SYMBOL]);
  }

  var IS_INDEXED_SYMBOL = '@@__IMMUTABLE_INDEXED__@@';

  function isIndexed(maybeIndexed) {
    return Boolean(maybeIndexed && maybeIndexed[IS_INDEXED_SYMBOL]);
  }

  function isAssociative(maybeAssociative) {
    return isKeyed(maybeAssociative) || isIndexed(maybeAssociative);
  }

  var Collection = function Collection(value) {
    return isCollection(value) ? value : Seq(value);
  };

  var KeyedCollection = /*@__PURE__*/(function (Collection) {
    function KeyedCollection(value) {
      return isKeyed(value) ? value : KeyedSeq(value);
    }

    if ( Collection ) KeyedCollection.__proto__ = Collection;
    KeyedCollection.prototype = Object.create( Collection && Collection.prototype );
    KeyedCollection.prototype.constructor = KeyedCollection;

    return KeyedCollection;
  }(Collection));

  var IndexedCollection = /*@__PURE__*/(function (Collection) {
    function IndexedCollection(value) {
      return isIndexed(value) ? value : IndexedSeq(value);
    }

    if ( Collection ) IndexedCollection.__proto__ = Collection;
    IndexedCollection.prototype = Object.create( Collection && Collection.prototype );
    IndexedCollection.prototype.constructor = IndexedCollection;

    return IndexedCollection;
  }(Collection));

  var SetCollection = /*@__PURE__*/(function (Collection) {
    function SetCollection(value) {
      return isCollection(value) && !isAssociative(value) ? value : SetSeq(value);
    }

    if ( Collection ) SetCollection.__proto__ = Collection;
    SetCollection.prototype = Object.create( Collection && Collection.prototype );
    SetCollection.prototype.constructor = SetCollection;

    return SetCollection;
  }(Collection));

  Collection.Keyed = KeyedCollection;
  Collection.Indexed = IndexedCollection;
  Collection.Set = SetCollection;

  var IS_SEQ_SYMBOL = '@@__IMMUTABLE_SEQ__@@';

  function isSeq(maybeSeq) {
    return Boolean(maybeSeq && maybeSeq[IS_SEQ_SYMBOL]);
  }

  var IS_RECORD_SYMBOL = '@@__IMMUTABLE_RECORD__@@';

  function isRecord(maybeRecord) {
    return Boolean(maybeRecord && maybeRecord[IS_RECORD_SYMBOL]);
  }

  function isImmutable(maybeImmutable) {
    return isCollection(maybeImmutable) || isRecord(maybeImmutable);
  }

  var IS_ORDERED_SYMBOL = '@@__IMMUTABLE_ORDERED__@@';

  function isOrdered(maybeOrdered) {
    return Boolean(maybeOrdered && maybeOrdered[IS_ORDERED_SYMBOL]);
  }

  var ITERATE_KEYS = 0;
  var ITERATE_VALUES = 1;
  var ITERATE_ENTRIES = 2;

  var REAL_ITERATOR_SYMBOL = typeof Symbol === 'function' && Symbol.iterator;
  var FAUX_ITERATOR_SYMBOL = '@@iterator';

  var ITERATOR_SYMBOL = REAL_ITERATOR_SYMBOL || FAUX_ITERATOR_SYMBOL;

  var Iterator = function Iterator(next) {
    this.next = next;
  };

  Iterator.prototype.toString = function toString () {
    return '[Iterator]';
  };

  Iterator.KEYS = ITERATE_KEYS;
  Iterator.VALUES = ITERATE_VALUES;
  Iterator.ENTRIES = ITERATE_ENTRIES;

  Iterator.prototype.inspect = Iterator.prototype.toSource = function () {
    return this.toString();
  };
  Iterator.prototype[ITERATOR_SYMBOL] = function () {
    return this;
  };

  function iteratorValue(type, k, v, iteratorResult) {
    var value = type === 0 ? k : type === 1 ? v : [k, v];
    iteratorResult
      ? (iteratorResult.value = value)
      : (iteratorResult = {
          value: value,
          done: false,
        });
    return iteratorResult;
  }

  function iteratorDone() {
    return { value: undefined, done: true };
  }

  function hasIterator(maybeIterable) {
    if (Array.isArray(maybeIterable)) {
      // IE11 trick as it does not support `Symbol.iterator`
      return true;
    }

    return !!getIteratorFn(maybeIterable);
  }

  function isIterator(maybeIterator) {
    return maybeIterator && typeof maybeIterator.next === 'function';
  }

  function getIterator(iterable) {
    var iteratorFn = getIteratorFn(iterable);
    return iteratorFn && iteratorFn.call(iterable);
  }

  function getIteratorFn(iterable) {
    var iteratorFn =
      iterable &&
      ((REAL_ITERATOR_SYMBOL && iterable[REAL_ITERATOR_SYMBOL]) ||
        iterable[FAUX_ITERATOR_SYMBOL]);
    if (typeof iteratorFn === 'function') {
      return iteratorFn;
    }
  }

  function isEntriesIterable(maybeIterable) {
    var iteratorFn = getIteratorFn(maybeIterable);
    return iteratorFn && iteratorFn === maybeIterable.entries;
  }

  function isKeysIterable(maybeIterable) {
    var iteratorFn = getIteratorFn(maybeIterable);
    return iteratorFn && iteratorFn === maybeIterable.keys;
  }

  var hasOwnProperty = Object.prototype.hasOwnProperty;

  function isArrayLike(value) {
    if (Array.isArray(value) || typeof value === 'string') {
      return true;
    }

    return (
      value &&
      typeof value === 'object' &&
      Number.isInteger(value.length) &&
      value.length >= 0 &&
      (value.length === 0
        ? // Only {length: 0} is considered Array-like.
          Object.keys(value).length === 1
        : // An object is only Array-like if it has a property where the last value
          // in the array-like may be found (which could be undefined).
          value.hasOwnProperty(value.length - 1))
    );
  }

  var Seq = /*@__PURE__*/(function (Collection) {
    function Seq(value) {
      return value === null || value === undefined
        ? emptySequence()
        : isImmutable(value)
        ? value.toSeq()
        : seqFromValue(value);
    }

    if ( Collection ) Seq.__proto__ = Collection;
    Seq.prototype = Object.create( Collection && Collection.prototype );
    Seq.prototype.constructor = Seq;

    Seq.prototype.toSeq = function toSeq () {
      return this;
    };

    Seq.prototype.toString = function toString () {
      return this.__toString('Seq {', '}');
    };

    Seq.prototype.cacheResult = function cacheResult () {
      if (!this._cache && this.__iterateUncached) {
        this._cache = this.entrySeq().toArray();
        this.size = this._cache.length;
      }
      return this;
    };

    // abstract __iterateUncached(fn, reverse)

    Seq.prototype.__iterate = function __iterate (fn, reverse) {
      var cache = this._cache;
      if (cache) {
        var size = cache.length;
        var i = 0;
        while (i !== size) {
          var entry = cache[reverse ? size - ++i : i++];
          if (fn(entry[1], entry[0], this) === false) {
            break;
          }
        }
        return i;
      }
      return this.__iterateUncached(fn, reverse);
    };

    // abstract __iteratorUncached(type, reverse)

    Seq.prototype.__iterator = function __iterator (type, reverse) {
      var cache = this._cache;
      if (cache) {
        var size = cache.length;
        var i = 0;
        return new Iterator(function () {
          if (i === size) {
            return iteratorDone();
          }
          var entry = cache[reverse ? size - ++i : i++];
          return iteratorValue(type, entry[0], entry[1]);
        });
      }
      return this.__iteratorUncached(type, reverse);
    };

    return Seq;
  }(Collection));

  var KeyedSeq = /*@__PURE__*/(function (Seq) {
    function KeyedSeq(value) {
      return value === null || value === undefined
        ? emptySequence().toKeyedSeq()
        : isCollection(value)
        ? isKeyed(value)
          ? value.toSeq()
          : value.fromEntrySeq()
        : isRecord(value)
        ? value.toSeq()
        : keyedSeqFromValue(value);
    }

    if ( Seq ) KeyedSeq.__proto__ = Seq;
    KeyedSeq.prototype = Object.create( Seq && Seq.prototype );
    KeyedSeq.prototype.constructor = KeyedSeq;

    KeyedSeq.prototype.toKeyedSeq = function toKeyedSeq () {
      return this;
    };

    return KeyedSeq;
  }(Seq));

  var IndexedSeq = /*@__PURE__*/(function (Seq) {
    function IndexedSeq(value) {
      return value === null || value === undefined
        ? emptySequence()
        : isCollection(value)
        ? isKeyed(value)
          ? value.entrySeq()
          : value.toIndexedSeq()
        : isRecord(value)
        ? value.toSeq().entrySeq()
        : indexedSeqFromValue(value);
    }

    if ( Seq ) IndexedSeq.__proto__ = Seq;
    IndexedSeq.prototype = Object.create( Seq && Seq.prototype );
    IndexedSeq.prototype.constructor = IndexedSeq;

    IndexedSeq.of = function of (/*...values*/) {
      return IndexedSeq(arguments);
    };

    IndexedSeq.prototype.toIndexedSeq = function toIndexedSeq () {
      return this;
    };

    IndexedSeq.prototype.toString = function toString () {
      return this.__toString('Seq [', ']');
    };

    return IndexedSeq;
  }(Seq));

  var SetSeq = /*@__PURE__*/(function (Seq) {
    function SetSeq(value) {
      return (
        isCollection(value) && !isAssociative(value) ? value : IndexedSeq(value)
      ).toSetSeq();
    }

    if ( Seq ) SetSeq.__proto__ = Seq;
    SetSeq.prototype = Object.create( Seq && Seq.prototype );
    SetSeq.prototype.constructor = SetSeq;

    SetSeq.of = function of (/*...values*/) {
      return SetSeq(arguments);
    };

    SetSeq.prototype.toSetSeq = function toSetSeq () {
      return this;
    };

    return SetSeq;
  }(Seq));

  Seq.isSeq = isSeq;
  Seq.Keyed = KeyedSeq;
  Seq.Set = SetSeq;
  Seq.Indexed = IndexedSeq;

  Seq.prototype[IS_SEQ_SYMBOL] = true;

  // #pragma Root Sequences

  var ArraySeq = /*@__PURE__*/(function (IndexedSeq) {
    function ArraySeq(array) {
      this._array = array;
      this.size = array.length;
    }

    if ( IndexedSeq ) ArraySeq.__proto__ = IndexedSeq;
    ArraySeq.prototype = Object.create( IndexedSeq && IndexedSeq.prototype );
    ArraySeq.prototype.constructor = ArraySeq;

    ArraySeq.prototype.get = function get (index, notSetValue) {
      return this.has(index) ? this._array[wrapIndex(this, index)] : notSetValue;
    };

    ArraySeq.prototype.__iterate = function __iterate (fn, reverse) {
      var array = this._array;
      var size = array.length;
      var i = 0;
      while (i !== size) {
        var ii = reverse ? size - ++i : i++;
        if (fn(array[ii], ii, this) === false) {
          break;
        }
      }
      return i;
    };

    ArraySeq.prototype.__iterator = function __iterator (type, reverse) {
      var array = this._array;
      var size = array.length;
      var i = 0;
      return new Iterator(function () {
        if (i === size) {
          return iteratorDone();
        }
        var ii = reverse ? size - ++i : i++;
        return iteratorValue(type, ii, array[ii]);
      });
    };

    return ArraySeq;
  }(IndexedSeq));

  var ObjectSeq = /*@__PURE__*/(function (KeyedSeq) {
    function ObjectSeq(object) {
      var keys = Object.keys(object);
      this._object = object;
      this._keys = keys;
      this.size = keys.length;
    }

    if ( KeyedSeq ) ObjectSeq.__proto__ = KeyedSeq;
    ObjectSeq.prototype = Object.create( KeyedSeq && KeyedSeq.prototype );
    ObjectSeq.prototype.constructor = ObjectSeq;

    ObjectSeq.prototype.get = function get (key, notSetValue) {
      if (notSetValue !== undefined && !this.has(key)) {
        return notSetValue;
      }
      return this._object[key];
    };

    ObjectSeq.prototype.has = function has (key) {
      return hasOwnProperty.call(this._object, key);
    };

    ObjectSeq.prototype.__iterate = function __iterate (fn, reverse) {
      var object = this._object;
      var keys = this._keys;
      var size = keys.length;
      var i = 0;
      while (i !== size) {
        var key = keys[reverse ? size - ++i : i++];
        if (fn(object[key], key, this) === false) {
          break;
        }
      }
      return i;
    };

    ObjectSeq.prototype.__iterator = function __iterator (type, reverse) {
      var object = this._object;
      var keys = this._keys;
      var size = keys.length;
      var i = 0;
      return new Iterator(function () {
        if (i === size) {
          return iteratorDone();
        }
        var key = keys[reverse ? size - ++i : i++];
        return iteratorValue(type, key, object[key]);
      });
    };

    return ObjectSeq;
  }(KeyedSeq));
  ObjectSeq.prototype[IS_ORDERED_SYMBOL] = true;

  var CollectionSeq = /*@__PURE__*/(function (IndexedSeq) {
    function CollectionSeq(collection) {
      this._collection = collection;
      this.size = collection.length || collection.size;
    }

    if ( IndexedSeq ) CollectionSeq.__proto__ = IndexedSeq;
    CollectionSeq.prototype = Object.create( IndexedSeq && IndexedSeq.prototype );
    CollectionSeq.prototype.constructor = CollectionSeq;

    CollectionSeq.prototype.__iterateUncached = function __iterateUncached (fn, reverse) {
      if (reverse) {
        return this.cacheResult().__iterate(fn, reverse);
      }
      var collection = this._collection;
      var iterator = getIterator(collection);
      var iterations = 0;
      if (isIterator(iterator)) {
        var step;
        while (!(step = iterator.next()).done) {
          if (fn(step.value, iterations++, this) === false) {
            break;
          }
        }
      }
      return iterations;
    };

    CollectionSeq.prototype.__iteratorUncached = function __iteratorUncached (type, reverse) {
      if (reverse) {
        return this.cacheResult().__iterator(type, reverse);
      }
      var collection = this._collection;
      var iterator = getIterator(collection);
      if (!isIterator(iterator)) {
        return new Iterator(iteratorDone);
      }
      var iterations = 0;
      return new Iterator(function () {
        var step = iterator.next();
        return step.done ? step : iteratorValue(type, iterations++, step.value);
      });
    };

    return CollectionSeq;
  }(IndexedSeq));

  // # pragma Helper functions

  var EMPTY_SEQ;

  function emptySequence() {
    return EMPTY_SEQ || (EMPTY_SEQ = new ArraySeq([]));
  }

  function keyedSeqFromValue(value) {
    var seq = maybeIndexedSeqFromValue(value);
    if (seq) {
      return seq.fromEntrySeq();
    }
    if (typeof value === 'object') {
      return new ObjectSeq(value);
    }
    throw new TypeError(
      'Expected Array or collection object of [k, v] entries, or keyed object: ' +
        value
    );
  }

  function indexedSeqFromValue(value) {
    var seq = maybeIndexedSeqFromValue(value);
    if (seq) {
      return seq;
    }
    throw new TypeError(
      'Expected Array or collection object of values: ' + value
    );
  }

  function seqFromValue(value) {
    var seq = maybeIndexedSeqFromValue(value);
    if (seq) {
      return isEntriesIterable(value)
        ? seq.fromEntrySeq()
        : isKeysIterable(value)
        ? seq.toSetSeq()
        : seq;
    }
    if (typeof value === 'object') {
      return new ObjectSeq(value);
    }
    throw new TypeError(
      'Expected Array or collection object of values, or keyed object: ' + value
    );
  }

  function maybeIndexedSeqFromValue(value) {
    return isArrayLike(value)
      ? new ArraySeq(value)
      : hasIterator(value)
      ? new CollectionSeq(value)
      : undefined;
  }

  var IS_MAP_SYMBOL = '@@__IMMUTABLE_MAP__@@';

  function isMap(maybeMap) {
    return Boolean(maybeMap && maybeMap[IS_MAP_SYMBOL]);
  }

  function isOrderedMap(maybeOrderedMap) {
    return isMap(maybeOrderedMap) && isOrdered(maybeOrderedMap);
  }

  function isValueObject(maybeValue) {
    return Boolean(
      maybeValue &&
        typeof maybeValue.equals === 'function' &&
        typeof maybeValue.hashCode === 'function'
    );
  }

  /**
   * An extension of the "same-value" algorithm as [described for use by ES6 Map
   * and Set](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map#Key_equality)
   *
   * NaN is considered the same as NaN, however -0 and 0 are considered the same
   * value, which is different from the algorithm described by
   * [`Object.is`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is).
   *
   * This is extended further to allow Objects to describe the values they
   * represent, by way of `valueOf` or `equals` (and `hashCode`).
   *
   * Note: because of this extension, the key equality of Immutable.Map and the
   * value equality of Immutable.Set will differ from ES6 Map and Set.
   *
   * ### Defining custom values
   *
   * The easiest way to describe the value an object represents is by implementing
   * `valueOf`. For example, `Date` represents a value by returning a unix
   * timestamp for `valueOf`:
   *
   *     var date1 = new Date(1234567890000); // Fri Feb 13 2009 ...
   *     var date2 = new Date(1234567890000);
   *     date1.valueOf(); // 1234567890000
   *     assert( date1 !== date2 );
   *     assert( Immutable.is( date1, date2 ) );
   *
   * Note: overriding `valueOf` may have other implications if you use this object
   * where JavaScript expects a primitive, such as implicit string coercion.
   *
   * For more complex types, especially collections, implementing `valueOf` may
   * not be performant. An alternative is to implement `equals` and `hashCode`.
   *
   * `equals` takes another object, presumably of similar type, and returns true
   * if it is equal. Equality is symmetrical, so the same result should be
   * returned if this and the argument are flipped.
   *
   *     assert( a.equals(b) === b.equals(a) );
   *
   * `hashCode` returns a 32bit integer number representing the object which will
   * be used to determine how to store the value object in a Map or Set. You must
   * provide both or neither methods, one must not exist without the other.
   *
   * Also, an important relationship between these methods must be upheld: if two
   * values are equal, they *must* return the same hashCode. If the values are not
   * equal, they might have the same hashCode; this is called a hash collision,
   * and while undesirable for performance reasons, it is acceptable.
   *
   *     if (a.equals(b)) {
   *       assert( a.hashCode() === b.hashCode() );
   *     }
   *
   * All Immutable collections are Value Objects: they implement `equals()`
   * and `hashCode()`.
   */
  function is(valueA, valueB) {
    if (valueA === valueB || (valueA !== valueA && valueB !== valueB)) {
      return true;
    }
    if (!valueA || !valueB) {
      return false;
    }
    if (
      typeof valueA.valueOf === 'function' &&
      typeof valueB.valueOf === 'function'
    ) {
      valueA = valueA.valueOf();
      valueB = valueB.valueOf();
      if (valueA === valueB || (valueA !== valueA && valueB !== valueB)) {
        return true;
      }
      if (!valueA || !valueB) {
        return false;
      }
    }
    return !!(
      isValueObject(valueA) &&
      isValueObject(valueB) &&
      valueA.equals(valueB)
    );
  }

  var imul =
    typeof Math.imul === 'function' && Math.imul(0xffffffff, 2) === -2
      ? Math.imul
      : function imul(a, b) {
          a |= 0; // int
          b |= 0; // int
          var c = a & 0xffff;
          var d = b & 0xffff;
          // Shift by 0 fixes the sign on the high part.
          return (c * d + ((((a >>> 16) * d + c * (b >>> 16)) << 16) >>> 0)) | 0; // int
        };

  // v8 has an optimization for storing 31-bit signed numbers.
  // Values which have either 00 or 11 as the high order bits qualify.
  // This function drops the highest order bit in a signed number, maintaining
  // the sign bit.
  function smi(i32) {
    return ((i32 >>> 1) & 0x40000000) | (i32 & 0xbfffffff);
  }

  var defaultValueOf = Object.prototype.valueOf;

  function hash(o) {
    if (o == null) {
      return hashNullish(o);
    }

    if (typeof o.hashCode === 'function') {
      // Drop any high bits from accidentally long hash codes.
      return smi(o.hashCode(o));
    }

    var v = valueOf(o);

    if (v == null) {
      return hashNullish(v);
    }

    switch (typeof v) {
      case 'boolean':
        // The hash values for built-in constants are a 1 value for each 5-byte
        // shift region expect for the first, which encodes the value. This
        // reduces the odds of a hash collision for these common values.
        return v ? 0x42108421 : 0x42108420;
      case 'number':
        return hashNumber(v);
      case 'string':
        return v.length > STRING_HASH_CACHE_MIN_STRLEN
          ? cachedHashString(v)
          : hashString(v);
      case 'object':
      case 'function':
        return hashJSObj(v);
      case 'symbol':
        return hashSymbol(v);
      default:
        if (typeof v.toString === 'function') {
          return hashString(v.toString());
        }
        throw new Error('Value type ' + typeof v + ' cannot be hashed.');
    }
  }

  function hashNullish(nullish) {
    return nullish === null ? 0x42108422 : /* undefined */ 0x42108423;
  }

  // Compress arbitrarily large numbers into smi hashes.
  function hashNumber(n) {
    if (n !== n || n === Infinity) {
      return 0;
    }
    var hash = n | 0;
    if (hash !== n) {
      hash ^= n * 0xffffffff;
    }
    while (n > 0xffffffff) {
      n /= 0xffffffff;
      hash ^= n;
    }
    return smi(hash);
  }

  function cachedHashString(string) {
    var hashed = stringHashCache[string];
    if (hashed === undefined) {
      hashed = hashString(string);
      if (STRING_HASH_CACHE_SIZE === STRING_HASH_CACHE_MAX_SIZE) {
        STRING_HASH_CACHE_SIZE = 0;
        stringHashCache = {};
      }
      STRING_HASH_CACHE_SIZE++;
      stringHashCache[string] = hashed;
    }
    return hashed;
  }

  // http://jsperf.com/hashing-strings
  function hashString(string) {
    // This is the hash from JVM
    // The hash code for a string is computed as
    // s[0] * 31 ^ (n - 1) + s[1] * 31 ^ (n - 2) + ... + s[n - 1],
    // where s[i] is the ith character of the string and n is the length of
    // the string. We "mod" the result to make it between 0 (inclusive) and 2^31
    // (exclusive) by dropping high bits.
    var hashed = 0;
    for (var ii = 0; ii < string.length; ii++) {
      hashed = (31 * hashed + string.charCodeAt(ii)) | 0;
    }
    return smi(hashed);
  }

  function hashSymbol(sym) {
    var hashed = symbolMap[sym];
    if (hashed !== undefined) {
      return hashed;
    }

    hashed = nextHash();

    symbolMap[sym] = hashed;

    return hashed;
  }

  function hashJSObj(obj) {
    var hashed;
    if (usingWeakMap) {
      hashed = weakMap.get(obj);
      if (hashed !== undefined) {
        return hashed;
      }
    }

    hashed = obj[UID_HASH_KEY];
    if (hashed !== undefined) {
      return hashed;
    }

    if (!canDefineProperty) {
      hashed = obj.propertyIsEnumerable && obj.propertyIsEnumerable[UID_HASH_KEY];
      if (hashed !== undefined) {
        return hashed;
      }

      hashed = getIENodeHash(obj);
      if (hashed !== undefined) {
        return hashed;
      }
    }

    hashed = nextHash();

    if (usingWeakMap) {
      weakMap.set(obj, hashed);
    } else if (isExtensible !== undefined && isExtensible(obj) === false) {
      throw new Error('Non-extensible objects are not allowed as keys.');
    } else if (canDefineProperty) {
      Object.defineProperty(obj, UID_HASH_KEY, {
        enumerable: false,
        configurable: false,
        writable: false,
        value: hashed,
      });
    } else if (
      obj.propertyIsEnumerable !== undefined &&
      obj.propertyIsEnumerable === obj.constructor.prototype.propertyIsEnumerable
    ) {
      // Since we can't define a non-enumerable property on the object
      // we'll hijack one of the less-used non-enumerable properties to
      // save our hash on it. Since this is a function it will not show up in
      // `JSON.stringify` which is what we want.
      obj.propertyIsEnumerable = function () {
        return this.constructor.prototype.propertyIsEnumerable.apply(
          this,
          arguments
        );
      };
      obj.propertyIsEnumerable[UID_HASH_KEY] = hashed;
    } else if (obj.nodeType !== undefined) {
      // At this point we couldn't get the IE `uniqueID` to use as a hash
      // and we couldn't use a non-enumerable property to exploit the
      // dontEnum bug so we simply add the `UID_HASH_KEY` on the node
      // itself.
      obj[UID_HASH_KEY] = hashed;
    } else {
      throw new Error('Unable to set a non-enumerable property on object.');
    }

    return hashed;
  }

  // Get references to ES5 object methods.
  var isExtensible = Object.isExtensible;

  // True if Object.defineProperty works as expected. IE8 fails this test.
  var canDefineProperty = (function () {
    try {
      Object.defineProperty({}, '@', {});
      return true;
    } catch (e) {
      return false;
    }
  })();

  // IE has a `uniqueID` property on DOM nodes. We can construct the hash from it
  // and avoid memory leaks from the IE cloneNode bug.
  function getIENodeHash(node) {
    if (node && node.nodeType > 0) {
      switch (node.nodeType) {
        case 1: // Element
          return node.uniqueID;
        case 9: // Document
          return node.documentElement && node.documentElement.uniqueID;
      }
    }
  }

  function valueOf(obj) {
    return obj.valueOf !== defaultValueOf && typeof obj.valueOf === 'function'
      ? obj.valueOf(obj)
      : obj;
  }

  function nextHash() {
    var nextHash = ++_objHashUID;
    if (_objHashUID & 0x40000000) {
      _objHashUID = 0;
    }
    return nextHash;
  }

  // If possible, use a WeakMap.
  var usingWeakMap = typeof WeakMap === 'function';
  var weakMap;
  if (usingWeakMap) {
    weakMap = new WeakMap();
  }

  var symbolMap = Object.create(null);

  var _objHashUID = 0;

  var UID_HASH_KEY = '__immutablehash__';
  if (typeof Symbol === 'function') {
    UID_HASH_KEY = Symbol(UID_HASH_KEY);
  }

  var STRING_HASH_CACHE_MIN_STRLEN = 16;
  var STRING_HASH_CACHE_MAX_SIZE = 255;
  var STRING_HASH_CACHE_SIZE = 0;
  var stringHashCache = {};

  var ToKeyedSequence = /*@__PURE__*/(function (KeyedSeq) {
    function ToKeyedSequence(indexed, useKeys) {
      this._iter = indexed;
      this._useKeys = useKeys;
      this.size = indexed.size;
    }

    if ( KeyedSeq ) ToKeyedSequence.__proto__ = KeyedSeq;
    ToKeyedSequence.prototype = Object.create( KeyedSeq && KeyedSeq.prototype );
    ToKeyedSequence.prototype.constructor = ToKeyedSequence;

    ToKeyedSequence.prototype.get = function get (key, notSetValue) {
      return this._iter.get(key, notSetValue);
    };

    ToKeyedSequence.prototype.has = function has (key) {
      return this._iter.has(key);
    };

    ToKeyedSequence.prototype.valueSeq = function valueSeq () {
      return this._iter.valueSeq();
    };

    ToKeyedSequence.prototype.reverse = function reverse () {
      var this$1$1 = this;

      var reversedSequence = reverseFactory(this, true);
      if (!this._useKeys) {
        reversedSequence.valueSeq = function () { return this$1$1._iter.toSeq().reverse(); };
      }
      return reversedSequence;
    };

    ToKeyedSequence.prototype.map = function map (mapper, context) {
      var this$1$1 = this;

      var mappedSequence = mapFactory(this, mapper, context);
      if (!this._useKeys) {
        mappedSequence.valueSeq = function () { return this$1$1._iter.toSeq().map(mapper, context); };
      }
      return mappedSequence;
    };

    ToKeyedSequence.prototype.__iterate = function __iterate (fn, reverse) {
      var this$1$1 = this;

      return this._iter.__iterate(function (v, k) { return fn(v, k, this$1$1); }, reverse);
    };

    ToKeyedSequence.prototype.__iterator = function __iterator (type, reverse) {
      return this._iter.__iterator(type, reverse);
    };

    return ToKeyedSequence;
  }(KeyedSeq));
  ToKeyedSequence.prototype[IS_ORDERED_SYMBOL] = true;

  var ToIndexedSequence = /*@__PURE__*/(function (IndexedSeq) {
    function ToIndexedSequence(iter) {
      this._iter = iter;
      this.size = iter.size;
    }

    if ( IndexedSeq ) ToIndexedSequence.__proto__ = IndexedSeq;
    ToIndexedSequence.prototype = Object.create( IndexedSeq && IndexedSeq.prototype );
    ToIndexedSequence.prototype.constructor = ToIndexedSequence;

    ToIndexedSequence.prototype.includes = function includes (value) {
      return this._iter.includes(value);
    };

    ToIndexedSequence.prototype.__iterate = function __iterate (fn, reverse) {
      var this$1$1 = this;

      var i = 0;
      reverse && ensureSize(this);
      return this._iter.__iterate(
        function (v) { return fn(v, reverse ? this$1$1.size - ++i : i++, this$1$1); },
        reverse
      );
    };

    ToIndexedSequence.prototype.__iterator = function __iterator (type, reverse) {
      var this$1$1 = this;

      var iterator = this._iter.__iterator(ITERATE_VALUES, reverse);
      var i = 0;
      reverse && ensureSize(this);
      return new Iterator(function () {
        var step = iterator.next();
        return step.done
          ? step
          : iteratorValue(
              type,
              reverse ? this$1$1.size - ++i : i++,
              step.value,
              step
            );
      });
    };

    return ToIndexedSequence;
  }(IndexedSeq));

  var ToSetSequence = /*@__PURE__*/(function (SetSeq) {
    function ToSetSequence(iter) {
      this._iter = iter;
      this.size = iter.size;
    }

    if ( SetSeq ) ToSetSequence.__proto__ = SetSeq;
    ToSetSequence.prototype = Object.create( SetSeq && SetSeq.prototype );
    ToSetSequence.prototype.constructor = ToSetSequence;

    ToSetSequence.prototype.has = function has (key) {
      return this._iter.includes(key);
    };

    ToSetSequence.prototype.__iterate = function __iterate (fn, reverse) {
      var this$1$1 = this;

      return this._iter.__iterate(function (v) { return fn(v, v, this$1$1); }, reverse);
    };

    ToSetSequence.prototype.__iterator = function __iterator (type, reverse) {
      var iterator = this._iter.__iterator(ITERATE_VALUES, reverse);
      return new Iterator(function () {
        var step = iterator.next();
        return step.done
          ? step
          : iteratorValue(type, step.value, step.value, step);
      });
    };

    return ToSetSequence;
  }(SetSeq));

  var FromEntriesSequence = /*@__PURE__*/(function (KeyedSeq) {
    function FromEntriesSequence(entries) {
      this._iter = entries;
      this.size = entries.size;
    }

    if ( KeyedSeq ) FromEntriesSequence.__proto__ = KeyedSeq;
    FromEntriesSequence.prototype = Object.create( KeyedSeq && KeyedSeq.prototype );
    FromEntriesSequence.prototype.constructor = FromEntriesSequence;

    FromEntriesSequence.prototype.entrySeq = function entrySeq () {
      return this._iter.toSeq();
    };

    FromEntriesSequence.prototype.__iterate = function __iterate (fn, reverse) {
      var this$1$1 = this;

      return this._iter.__iterate(function (entry) {
        // Check if entry exists first so array access doesn't throw for holes
        // in the parent iteration.
        if (entry) {
          validateEntry(entry);
          var indexedCollection = isCollection(entry);
          return fn(
            indexedCollection ? entry.get(1) : entry[1],
            indexedCollection ? entry.get(0) : entry[0],
            this$1$1
          );
        }
      }, reverse);
    };

    FromEntriesSequence.prototype.__iterator = function __iterator (type, reverse) {
      var iterator = this._iter.__iterator(ITERATE_VALUES, reverse);
      return new Iterator(function () {
        while (true) {
          var step = iterator.next();
          if (step.done) {
            return step;
          }
          var entry = step.value;
          // Check if entry exists first so array access doesn't throw for holes
          // in the parent iteration.
          if (entry) {
            validateEntry(entry);
            var indexedCollection = isCollection(entry);
            return iteratorValue(
              type,
              indexedCollection ? entry.get(0) : entry[0],
              indexedCollection ? entry.get(1) : entry[1],
              step
            );
          }
        }
      });
    };

    return FromEntriesSequence;
  }(KeyedSeq));

  ToIndexedSequence.prototype.cacheResult =
    ToKeyedSequence.prototype.cacheResult =
    ToSetSequence.prototype.cacheResult =
    FromEntriesSequence.prototype.cacheResult =
      cacheResultThrough;

  function flipFactory(collection) {
    var flipSequence = makeSequence(collection);
    flipSequence._iter = collection;
    flipSequence.size = collection.size;
    flipSequence.flip = function () { return collection; };
    flipSequence.reverse = function () {
      var reversedSequence = collection.reverse.apply(this); // super.reverse()
      reversedSequence.flip = function () { return collection.reverse(); };
      return reversedSequence;
    };
    flipSequence.has = function (key) { return collection.includes(key); };
    flipSequence.includes = function (key) { return collection.has(key); };
    flipSequence.cacheResult = cacheResultThrough;
    flipSequence.__iterateUncached = function (fn, reverse) {
      var this$1$1 = this;

      return collection.__iterate(function (v, k) { return fn(k, v, this$1$1) !== false; }, reverse);
    };
    flipSequence.__iteratorUncached = function (type, reverse) {
      if (type === ITERATE_ENTRIES) {
        var iterator = collection.__iterator(type, reverse);
        return new Iterator(function () {
          var step = iterator.next();
          if (!step.done) {
            var k = step.value[0];
            step.value[0] = step.value[1];
            step.value[1] = k;
          }
          return step;
        });
      }
      return collection.__iterator(
        type === ITERATE_VALUES ? ITERATE_KEYS : ITERATE_VALUES,
        reverse
      );
    };
    return flipSequence;
  }

  function mapFactory(collection, mapper, context) {
    var mappedSequence = makeSequence(collection);
    mappedSequence.size = collection.size;
    mappedSequence.has = function (key) { return collection.has(key); };
    mappedSequence.get = function (key, notSetValue) {
      var v = collection.get(key, NOT_SET);
      return v === NOT_SET
        ? notSetValue
        : mapper.call(context, v, key, collection);
    };
    mappedSequence.__iterateUncached = function (fn, reverse) {
      var this$1$1 = this;

      return collection.__iterate(
        function (v, k, c) { return fn(mapper.call(context, v, k, c), k, this$1$1) !== false; },
        reverse
      );
    };
    mappedSequence.__iteratorUncached = function (type, reverse) {
      var iterator = collection.__iterator(ITERATE_ENTRIES, reverse);
      return new Iterator(function () {
        var step = iterator.next();
        if (step.done) {
          return step;
        }
        var entry = step.value;
        var key = entry[0];
        return iteratorValue(
          type,
          key,
          mapper.call(context, entry[1], key, collection),
          step
        );
      });
    };
    return mappedSequence;
  }

  function reverseFactory(collection, useKeys) {
    var this$1$1 = this;

    var reversedSequence = makeSequence(collection);
    reversedSequence._iter = collection;
    reversedSequence.size = collection.size;
    reversedSequence.reverse = function () { return collection; };
    if (collection.flip) {
      reversedSequence.flip = function () {
        var flipSequence = flipFactory(collection);
        flipSequence.reverse = function () { return collection.flip(); };
        return flipSequence;
      };
    }
    reversedSequence.get = function (key, notSetValue) { return collection.get(useKeys ? key : -1 - key, notSetValue); };
    reversedSequence.has = function (key) { return collection.has(useKeys ? key : -1 - key); };
    reversedSequence.includes = function (value) { return collection.includes(value); };
    reversedSequence.cacheResult = cacheResultThrough;
    reversedSequence.__iterate = function (fn, reverse) {
      var this$1$1 = this;

      var i = 0;
      reverse && ensureSize(collection);
      return collection.__iterate(
        function (v, k) { return fn(v, useKeys ? k : reverse ? this$1$1.size - ++i : i++, this$1$1); },
        !reverse
      );
    };
    reversedSequence.__iterator = function (type, reverse) {
      var i = 0;
      reverse && ensureSize(collection);
      var iterator = collection.__iterator(ITERATE_ENTRIES, !reverse);
      return new Iterator(function () {
        var step = iterator.next();
        if (step.done) {
          return step;
        }
        var entry = step.value;
        return iteratorValue(
          type,
          useKeys ? entry[0] : reverse ? this$1$1.size - ++i : i++,
          entry[1],
          step
        );
      });
    };
    return reversedSequence;
  }

  function filterFactory(collection, predicate, context, useKeys) {
    var filterSequence = makeSequence(collection);
    if (useKeys) {
      filterSequence.has = function (key) {
        var v = collection.get(key, NOT_SET);
        return v !== NOT_SET && !!predicate.call(context, v, key, collection);
      };
      filterSequence.get = function (key, notSetValue) {
        var v = collection.get(key, NOT_SET);
        return v !== NOT_SET && predicate.call(context, v, key, collection)
          ? v
          : notSetValue;
      };
    }
    filterSequence.__iterateUncached = function (fn, reverse) {
      var this$1$1 = this;

      var iterations = 0;
      collection.__iterate(function (v, k, c) {
        if (predicate.call(context, v, k, c)) {
          iterations++;
          return fn(v, useKeys ? k : iterations - 1, this$1$1);
        }
      }, reverse);
      return iterations;
    };
    filterSequence.__iteratorUncached = function (type, reverse) {
      var iterator = collection.__iterator(ITERATE_ENTRIES, reverse);
      var iterations = 0;
      return new Iterator(function () {
        while (true) {
          var step = iterator.next();
          if (step.done) {
            return step;
          }
          var entry = step.value;
          var key = entry[0];
          var value = entry[1];
          if (predicate.call(context, value, key, collection)) {
            return iteratorValue(type, useKeys ? key : iterations++, value, step);
          }
        }
      });
    };
    return filterSequence;
  }

  function countByFactory(collection, grouper, context) {
    var groups = Map().asMutable();
    collection.__iterate(function (v, k) {
      groups.update(grouper.call(context, v, k, collection), 0, function (a) { return a + 1; });
    });
    return groups.asImmutable();
  }

  function groupByFactory(collection, grouper, context) {
    var isKeyedIter = isKeyed(collection);
    var groups = (isOrdered(collection) ? OrderedMap() : Map()).asMutable();
    collection.__iterate(function (v, k) {
      groups.update(
        grouper.call(context, v, k, collection),
        function (a) { return ((a = a || []), a.push(isKeyedIter ? [k, v] : v), a); }
      );
    });
    var coerce = collectionClass(collection);
    return groups.map(function (arr) { return reify(collection, coerce(arr)); }).asImmutable();
  }

  function sliceFactory(collection, begin, end, useKeys) {
    var originalSize = collection.size;

    if (wholeSlice(begin, end, originalSize)) {
      return collection;
    }

    var resolvedBegin = resolveBegin(begin, originalSize);
    var resolvedEnd = resolveEnd(end, originalSize);

    // begin or end will be NaN if they were provided as negative numbers and
    // this collection's size is unknown. In that case, cache first so there is
    // a known size and these do not resolve to NaN.
    if (resolvedBegin !== resolvedBegin || resolvedEnd !== resolvedEnd) {
      return sliceFactory(collection.toSeq().cacheResult(), begin, end, useKeys);
    }

    // Note: resolvedEnd is undefined when the original sequence's length is
    // unknown and this slice did not supply an end and should contain all
    // elements after resolvedBegin.
    // In that case, resolvedSize will be NaN and sliceSize will remain undefined.
    var resolvedSize = resolvedEnd - resolvedBegin;
    var sliceSize;
    if (resolvedSize === resolvedSize) {
      sliceSize = resolvedSize < 0 ? 0 : resolvedSize;
    }

    var sliceSeq = makeSequence(collection);

    // If collection.size is undefined, the size of the realized sliceSeq is
    // unknown at this point unless the number of items to slice is 0
    sliceSeq.size =
      sliceSize === 0 ? sliceSize : (collection.size && sliceSize) || undefined;

    if (!useKeys && isSeq(collection) && sliceSize >= 0) {
      sliceSeq.get = function (index, notSetValue) {
        index = wrapIndex(this, index);
        return index >= 0 && index < sliceSize
          ? collection.get(index + resolvedBegin, notSetValue)
          : notSetValue;
      };
    }

    sliceSeq.__iterateUncached = function (fn, reverse) {
      var this$1$1 = this;

      if (sliceSize === 0) {
        return 0;
      }
      if (reverse) {
        return this.cacheResult().__iterate(fn, reverse);
      }
      var skipped = 0;
      var isSkipping = true;
      var iterations = 0;
      collection.__iterate(function (v, k) {
        if (!(isSkipping && (isSkipping = skipped++ < resolvedBegin))) {
          iterations++;
          return (
            fn(v, useKeys ? k : iterations - 1, this$1$1) !== false &&
            iterations !== sliceSize
          );
        }
      });
      return iterations;
    };

    sliceSeq.__iteratorUncached = function (type, reverse) {
      if (sliceSize !== 0 && reverse) {
        return this.cacheResult().__iterator(type, reverse);
      }
      // Don't bother instantiating parent iterator if taking 0.
      if (sliceSize === 0) {
        return new Iterator(iteratorDone);
      }
      var iterator = collection.__iterator(type, reverse);
      var skipped = 0;
      var iterations = 0;
      return new Iterator(function () {
        while (skipped++ < resolvedBegin) {
          iterator.next();
        }
        if (++iterations > sliceSize) {
          return iteratorDone();
        }
        var step = iterator.next();
        if (useKeys || type === ITERATE_VALUES || step.done) {
          return step;
        }
        if (type === ITERATE_KEYS) {
          return iteratorValue(type, iterations - 1, undefined, step);
        }
        return iteratorValue(type, iterations - 1, step.value[1], step);
      });
    };

    return sliceSeq;
  }

  function takeWhileFactory(collection, predicate, context) {
    var takeSequence = makeSequence(collection);
    takeSequence.__iterateUncached = function (fn, reverse) {
      var this$1$1 = this;

      if (reverse) {
        return this.cacheResult().__iterate(fn, reverse);
      }
      var iterations = 0;
      collection.__iterate(
        function (v, k, c) { return predicate.call(context, v, k, c) && ++iterations && fn(v, k, this$1$1); }
      );
      return iterations;
    };
    takeSequence.__iteratorUncached = function (type, reverse) {
      var this$1$1 = this;

      if (reverse) {
        return this.cacheResult().__iterator(type, reverse);
      }
      var iterator = collection.__iterator(ITERATE_ENTRIES, reverse);
      var iterating = true;
      return new Iterator(function () {
        if (!iterating) {
          return iteratorDone();
        }
        var step = iterator.next();
        if (step.done) {
          return step;
        }
        var entry = step.value;
        var k = entry[0];
        var v = entry[1];
        if (!predicate.call(context, v, k, this$1$1)) {
          iterating = false;
          return iteratorDone();
        }
        return type === ITERATE_ENTRIES ? step : iteratorValue(type, k, v, step);
      });
    };
    return takeSequence;
  }

  function skipWhileFactory(collection, predicate, context, useKeys) {
    var skipSequence = makeSequence(collection);
    skipSequence.__iterateUncached = function (fn, reverse) {
      var this$1$1 = this;

      if (reverse) {
        return this.cacheResult().__iterate(fn, reverse);
      }
      var isSkipping = true;
      var iterations = 0;
      collection.__iterate(function (v, k, c) {
        if (!(isSkipping && (isSkipping = predicate.call(context, v, k, c)))) {
          iterations++;
          return fn(v, useKeys ? k : iterations - 1, this$1$1);
        }
      });
      return iterations;
    };
    skipSequence.__iteratorUncached = function (type, reverse) {
      var this$1$1 = this;

      if (reverse) {
        return this.cacheResult().__iterator(type, reverse);
      }
      var iterator = collection.__iterator(ITERATE_ENTRIES, reverse);
      var skipping = true;
      var iterations = 0;
      return new Iterator(function () {
        var step;
        var k;
        var v;
        do {
          step = iterator.next();
          if (step.done) {
            if (useKeys || type === ITERATE_VALUES) {
              return step;
            }
            if (type === ITERATE_KEYS) {
              return iteratorValue(type, iterations++, undefined, step);
            }
            return iteratorValue(type, iterations++, step.value[1], step);
          }
          var entry = step.value;
          k = entry[0];
          v = entry[1];
          skipping && (skipping = predicate.call(context, v, k, this$1$1));
        } while (skipping);
        return type === ITERATE_ENTRIES ? step : iteratorValue(type, k, v, step);
      });
    };
    return skipSequence;
  }

  function concatFactory(collection, values) {
    var isKeyedCollection = isKeyed(collection);
    var iters = [collection]
      .concat(values)
      .map(function (v) {
        if (!isCollection(v)) {
          v = isKeyedCollection
            ? keyedSeqFromValue(v)
            : indexedSeqFromValue(Array.isArray(v) ? v : [v]);
        } else if (isKeyedCollection) {
          v = KeyedCollection(v);
        }
        return v;
      })
      .filter(function (v) { return v.size !== 0; });

    if (iters.length === 0) {
      return collection;
    }

    if (iters.length === 1) {
      var singleton = iters[0];
      if (
        singleton === collection ||
        (isKeyedCollection && isKeyed(singleton)) ||
        (isIndexed(collection) && isIndexed(singleton))
      ) {
        return singleton;
      }
    }

    var concatSeq = new ArraySeq(iters);
    if (isKeyedCollection) {
      concatSeq = concatSeq.toKeyedSeq();
    } else if (!isIndexed(collection)) {
      concatSeq = concatSeq.toSetSeq();
    }
    concatSeq = concatSeq.flatten(true);
    concatSeq.size = iters.reduce(function (sum, seq) {
      if (sum !== undefined) {
        var size = seq.size;
        if (size !== undefined) {
          return sum + size;
        }
      }
    }, 0);
    return concatSeq;
  }

  function flattenFactory(collection, depth, useKeys) {
    var flatSequence = makeSequence(collection);
    flatSequence.__iterateUncached = function (fn, reverse) {
      if (reverse) {
        return this.cacheResult().__iterate(fn, reverse);
      }
      var iterations = 0;
      var stopped = false;
      function flatDeep(iter, currentDepth) {
        iter.__iterate(function (v, k) {
          if ((!depth || currentDepth < depth) && isCollection(v)) {
            flatDeep(v, currentDepth + 1);
          } else {
            iterations++;
            if (fn(v, useKeys ? k : iterations - 1, flatSequence) === false) {
              stopped = true;
            }
          }
          return !stopped;
        }, reverse);
      }
      flatDeep(collection, 0);
      return iterations;
    };
    flatSequence.__iteratorUncached = function (type, reverse) {
      if (reverse) {
        return this.cacheResult().__iterator(type, reverse);
      }
      var iterator = collection.__iterator(type, reverse);
      var stack = [];
      var iterations = 0;
      return new Iterator(function () {
        while (iterator) {
          var step = iterator.next();
          if (step.done !== false) {
            iterator = stack.pop();
            continue;
          }
          var v = step.value;
          if (type === ITERATE_ENTRIES) {
            v = v[1];
          }
          if ((!depth || stack.length < depth) && isCollection(v)) {
            stack.push(iterator);
            iterator = v.__iterator(type, reverse);
          } else {
            return useKeys ? step : iteratorValue(type, iterations++, v, step);
          }
        }
        return iteratorDone();
      });
    };
    return flatSequence;
  }

  function flatMapFactory(collection, mapper, context) {
    var coerce = collectionClass(collection);
    return collection
      .toSeq()
      .map(function (v, k) { return coerce(mapper.call(context, v, k, collection)); })
      .flatten(true);
  }

  function interposeFactory(collection, separator) {
    var interposedSequence = makeSequence(collection);
    interposedSequence.size = collection.size && collection.size * 2 - 1;
    interposedSequence.__iterateUncached = function (fn, reverse) {
      var this$1$1 = this;

      var iterations = 0;
      collection.__iterate(
        function (v) { return (!iterations || fn(separator, iterations++, this$1$1) !== false) &&
          fn(v, iterations++, this$1$1) !== false; },
        reverse
      );
      return iterations;
    };
    interposedSequence.__iteratorUncached = function (type, reverse) {
      var iterator = collection.__iterator(ITERATE_VALUES, reverse);
      var iterations = 0;
      var step;
      return new Iterator(function () {
        if (!step || iterations % 2) {
          step = iterator.next();
          if (step.done) {
            return step;
          }
        }
        return iterations % 2
          ? iteratorValue(type, iterations++, separator)
          : iteratorValue(type, iterations++, step.value, step);
      });
    };
    return interposedSequence;
  }

  function sortFactory(collection, comparator, mapper) {
    if (!comparator) {
      comparator = defaultComparator;
    }
    var isKeyedCollection = isKeyed(collection);
    var index = 0;
    var entries = collection
      .toSeq()
      .map(function (v, k) { return [k, v, index++, mapper ? mapper(v, k, collection) : v]; })
      .valueSeq()
      .toArray();
    entries
      .sort(function (a, b) { return comparator(a[3], b[3]) || a[2] - b[2]; })
      .forEach(
        isKeyedCollection
          ? function (v, i) {
              entries[i].length = 2;
            }
          : function (v, i) {
              entries[i] = v[1];
            }
      );
    return isKeyedCollection
      ? KeyedSeq(entries)
      : isIndexed(collection)
      ? IndexedSeq(entries)
      : SetSeq(entries);
  }

  function maxFactory(collection, comparator, mapper) {
    if (!comparator) {
      comparator = defaultComparator;
    }
    if (mapper) {
      var entry = collection
        .toSeq()
        .map(function (v, k) { return [v, mapper(v, k, collection)]; })
        .reduce(function (a, b) { return (maxCompare(comparator, a[1], b[1]) ? b : a); });
      return entry && entry[0];
    }
    return collection.reduce(function (a, b) { return (maxCompare(comparator, a, b) ? b : a); });
  }

  function maxCompare(comparator, a, b) {
    var comp = comparator(b, a);
    // b is considered the new max if the comparator declares them equal, but
    // they are not equal and b is in fact a nullish value.
    return (
      (comp === 0 && b !== a && (b === undefined || b === null || b !== b)) ||
      comp > 0
    );
  }

  function zipWithFactory(keyIter, zipper, iters, zipAll) {
    var zipSequence = makeSequence(keyIter);
    var sizes = new ArraySeq(iters).map(function (i) { return i.size; });
    zipSequence.size = zipAll ? sizes.max() : sizes.min();
    // Note: this a generic base implementation of __iterate in terms of
    // __iterator which may be more generically useful in the future.
    zipSequence.__iterate = function (fn, reverse) {
      /* generic:
      var iterator = this.__iterator(ITERATE_ENTRIES, reverse);
      var step;
      var iterations = 0;
      while (!(step = iterator.next()).done) {
        iterations++;
        if (fn(step.value[1], step.value[0], this) === false) {
          break;
        }
      }
      return iterations;
      */
      // indexed:
      var iterator = this.__iterator(ITERATE_VALUES, reverse);
      var step;
      var iterations = 0;
      while (!(step = iterator.next()).done) {
        if (fn(step.value, iterations++, this) === false) {
          break;
        }
      }
      return iterations;
    };
    zipSequence.__iteratorUncached = function (type, reverse) {
      var iterators = iters.map(
        function (i) { return ((i = Collection(i)), getIterator(reverse ? i.reverse() : i)); }
      );
      var iterations = 0;
      var isDone = false;
      return new Iterator(function () {
        var steps;
        if (!isDone) {
          steps = iterators.map(function (i) { return i.next(); });
          isDone = zipAll ? steps.every(function (s) { return s.done; }) : steps.some(function (s) { return s.done; });
        }
        if (isDone) {
          return iteratorDone();
        }
        return iteratorValue(
          type,
          iterations++,
          zipper.apply(
            null,
            steps.map(function (s) { return s.value; })
          )
        );
      });
    };
    return zipSequence;
  }

  // #pragma Helper Functions

  function reify(iter, seq) {
    return iter === seq ? iter : isSeq(iter) ? seq : iter.constructor(seq);
  }

  function validateEntry(entry) {
    if (entry !== Object(entry)) {
      throw new TypeError('Expected [K, V] tuple: ' + entry);
    }
  }

  function collectionClass(collection) {
    return isKeyed(collection)
      ? KeyedCollection
      : isIndexed(collection)
      ? IndexedCollection
      : SetCollection;
  }

  function makeSequence(collection) {
    return Object.create(
      (isKeyed(collection)
        ? KeyedSeq
        : isIndexed(collection)
        ? IndexedSeq
        : SetSeq
      ).prototype
    );
  }

  function cacheResultThrough() {
    if (this._iter.cacheResult) {
      this._iter.cacheResult();
      this.size = this._iter.size;
      return this;
    }
    return Seq.prototype.cacheResult.call(this);
  }

  function defaultComparator(a, b) {
    if (a === undefined && b === undefined) {
      return 0;
    }

    if (a === undefined) {
      return 1;
    }

    if (b === undefined) {
      return -1;
    }

    return a > b ? 1 : a < b ? -1 : 0;
  }

  function arrCopy(arr, offset) {
    offset = offset || 0;
    var len = Math.max(0, arr.length - offset);
    var newArr = new Array(len);
    for (var ii = 0; ii < len; ii++) {
      newArr[ii] = arr[ii + offset];
    }
    return newArr;
  }

  function invariant(condition, error) {
    if (!condition) { throw new Error(error); }
  }

  function assertNotInfinite(size) {
    invariant(
      size !== Infinity,
      'Cannot perform this action with an infinite size.'
    );
  }

  function coerceKeyPath(keyPath) {
    if (isArrayLike(keyPath) && typeof keyPath !== 'string') {
      return keyPath;
    }
    if (isOrdered(keyPath)) {
      return keyPath.toArray();
    }
    throw new TypeError(
      'Invalid keyPath: expected Ordered Collection or Array: ' + keyPath
    );
  }

  var toString = Object.prototype.toString;

  function isPlainObject(value) {
    // The base prototype's toString deals with Argument objects and native namespaces like Math
    if (
      !value ||
      typeof value !== 'object' ||
      toString.call(value) !== '[object Object]'
    ) {
      return false;
    }

    var proto = Object.getPrototypeOf(value);
    if (proto === null) {
      return true;
    }

    // Iteratively going up the prototype chain is needed for cross-realm environments (differing contexts, iframes, etc)
    var parentProto = proto;
    var nextProto = Object.getPrototypeOf(proto);
    while (nextProto !== null) {
      parentProto = nextProto;
      nextProto = Object.getPrototypeOf(parentProto);
    }
    return parentProto === proto;
  }

  /**
   * Returns true if the value is a potentially-persistent data structure, either
   * provided by Immutable.js or a plain Array or Object.
   */
  function isDataStructure(value) {
    return (
      typeof value === 'object' &&
      (isImmutable(value) || Array.isArray(value) || isPlainObject(value))
    );
  }

  function quoteString(value) {
    try {
      return typeof value === 'string' ? JSON.stringify(value) : String(value);
    } catch (_ignoreError) {
      return JSON.stringify(value);
    }
  }

  function has(collection, key) {
    return isImmutable(collection)
      ? collection.has(key)
      : isDataStructure(collection) && hasOwnProperty.call(collection, key);
  }

  function get(collection, key, notSetValue) {
    return isImmutable(collection)
      ? collection.get(key, notSetValue)
      : !has(collection, key)
      ? notSetValue
      : typeof collection.get === 'function'
      ? collection.get(key)
      : collection[key];
  }

  function shallowCopy(from) {
    if (Array.isArray(from)) {
      return arrCopy(from);
    }
    var to = {};
    for (var key in from) {
      if (hasOwnProperty.call(from, key)) {
        to[key] = from[key];
      }
    }
    return to;
  }

  function remove(collection, key) {
    if (!isDataStructure(collection)) {
      throw new TypeError(
        'Cannot update non-data-structure value: ' + collection
      );
    }
    if (isImmutable(collection)) {
      if (!collection.remove) {
        throw new TypeError(
          'Cannot update immutable value without .remove() method: ' + collection
        );
      }
      return collection.remove(key);
    }
    if (!hasOwnProperty.call(collection, key)) {
      return collection;
    }
    var collectionCopy = shallowCopy(collection);
    if (Array.isArray(collectionCopy)) {
      collectionCopy.splice(key, 1);
    } else {
      delete collectionCopy[key];
    }
    return collectionCopy;
  }

  function set(collection, key, value) {
    if (!isDataStructure(collection)) {
      throw new TypeError(
        'Cannot update non-data-structure value: ' + collection
      );
    }
    if (isImmutable(collection)) {
      if (!collection.set) {
        throw new TypeError(
          'Cannot update immutable value without .set() method: ' + collection
        );
      }
      return collection.set(key, value);
    }
    if (hasOwnProperty.call(collection, key) && value === collection[key]) {
      return collection;
    }
    var collectionCopy = shallowCopy(collection);
    collectionCopy[key] = value;
    return collectionCopy;
  }

  function updateIn$1(collection, keyPath, notSetValue, updater) {
    if (!updater) {
      updater = notSetValue;
      notSetValue = undefined;
    }
    var updatedValue = updateInDeeply(
      isImmutable(collection),
      collection,
      coerceKeyPath(keyPath),
      0,
      notSetValue,
      updater
    );
    return updatedValue === NOT_SET ? notSetValue : updatedValue;
  }

  function updateInDeeply(
    inImmutable,
    existing,
    keyPath,
    i,
    notSetValue,
    updater
  ) {
    var wasNotSet = existing === NOT_SET;
    if (i === keyPath.length) {
      var existingValue = wasNotSet ? notSetValue : existing;
      var newValue = updater(existingValue);
      return newValue === existingValue ? existing : newValue;
    }
    if (!wasNotSet && !isDataStructure(existing)) {
      throw new TypeError(
        'Cannot update within non-data-structure value in path [' +
          keyPath.slice(0, i).map(quoteString) +
          ']: ' +
          existing
      );
    }
    var key = keyPath[i];
    var nextExisting = wasNotSet ? NOT_SET : get(existing, key, NOT_SET);
    var nextUpdated = updateInDeeply(
      nextExisting === NOT_SET ? inImmutable : isImmutable(nextExisting),
      nextExisting,
      keyPath,
      i + 1,
      notSetValue,
      updater
    );
    return nextUpdated === nextExisting
      ? existing
      : nextUpdated === NOT_SET
      ? remove(existing, key)
      : set(
          wasNotSet ? (inImmutable ? emptyMap() : {}) : existing,
          key,
          nextUpdated
        );
  }

  function setIn$1(collection, keyPath, value) {
    return updateIn$1(collection, keyPath, NOT_SET, function () { return value; });
  }

  function setIn(keyPath, v) {
    return setIn$1(this, keyPath, v);
  }

  function removeIn(collection, keyPath) {
    return updateIn$1(collection, keyPath, function () { return NOT_SET; });
  }

  function deleteIn(keyPath) {
    return removeIn(this, keyPath);
  }

  function update$1(collection, key, notSetValue, updater) {
    return updateIn$1(collection, [key], notSetValue, updater);
  }

  function update(key, notSetValue, updater) {
    return arguments.length === 1
      ? key(this)
      : update$1(this, key, notSetValue, updater);
  }

  function updateIn(keyPath, notSetValue, updater) {
    return updateIn$1(this, keyPath, notSetValue, updater);
  }

  function merge$1() {
    var iters = [], len = arguments.length;
    while ( len-- ) iters[ len ] = arguments[ len ];

    return mergeIntoKeyedWith(this, iters);
  }

  function mergeWith$1(merger) {
    var iters = [], len = arguments.length - 1;
    while ( len-- > 0 ) iters[ len ] = arguments[ len + 1 ];

    if (typeof merger !== 'function') {
      throw new TypeError('Invalid merger function: ' + merger);
    }
    return mergeIntoKeyedWith(this, iters, merger);
  }

  function mergeIntoKeyedWith(collection, collections, merger) {
    var iters = [];
    for (var ii = 0; ii < collections.length; ii++) {
      var collection$1 = KeyedCollection(collections[ii]);
      if (collection$1.size !== 0) {
        iters.push(collection$1);
      }
    }
    if (iters.length === 0) {
      return collection;
    }
    if (
      collection.toSeq().size === 0 &&
      !collection.__ownerID &&
      iters.length === 1
    ) {
      return collection.constructor(iters[0]);
    }
    return collection.withMutations(function (collection) {
      var mergeIntoCollection = merger
        ? function (value, key) {
            update$1(collection, key, NOT_SET, function (oldVal) { return oldVal === NOT_SET ? value : merger(oldVal, value, key); }
            );
          }
        : function (value, key) {
            collection.set(key, value);
          };
      for (var ii = 0; ii < iters.length; ii++) {
        iters[ii].forEach(mergeIntoCollection);
      }
    });
  }

  function merge(collection) {
    var sources = [], len = arguments.length - 1;
    while ( len-- > 0 ) sources[ len ] = arguments[ len + 1 ];

    return mergeWithSources(collection, sources);
  }

  function mergeWith(merger, collection) {
    var sources = [], len = arguments.length - 2;
    while ( len-- > 0 ) sources[ len ] = arguments[ len + 2 ];

    return mergeWithSources(collection, sources, merger);
  }

  function mergeDeep$1(collection) {
    var sources = [], len = arguments.length - 1;
    while ( len-- > 0 ) sources[ len ] = arguments[ len + 1 ];

    return mergeDeepWithSources(collection, sources);
  }

  function mergeDeepWith$1(merger, collection) {
    var sources = [], len = arguments.length - 2;
    while ( len-- > 0 ) sources[ len ] = arguments[ len + 2 ];

    return mergeDeepWithSources(collection, sources, merger);
  }

  function mergeDeepWithSources(collection, sources, merger) {
    return mergeWithSources(collection, sources, deepMergerWith(merger));
  }

  function mergeWithSources(collection, sources, merger) {
    if (!isDataStructure(collection)) {
      throw new TypeError(
        'Cannot merge into non-data-structure value: ' + collection
      );
    }
    if (isImmutable(collection)) {
      return typeof merger === 'function' && collection.mergeWith
        ? collection.mergeWith.apply(collection, [ merger ].concat( sources ))
        : collection.merge
        ? collection.merge.apply(collection, sources)
        : collection.concat.apply(collection, sources);
    }
    var isArray = Array.isArray(collection);
    var merged = collection;
    var Collection = isArray ? IndexedCollection : KeyedCollection;
    var mergeItem = isArray
      ? function (value) {
          // Copy on write
          if (merged === collection) {
            merged = shallowCopy(merged);
          }
          merged.push(value);
        }
      : function (value, key) {
          var hasVal = hasOwnProperty.call(merged, key);
          var nextVal =
            hasVal && merger ? merger(merged[key], value, key) : value;
          if (!hasVal || nextVal !== merged[key]) {
            // Copy on write
            if (merged === collection) {
              merged = shallowCopy(merged);
            }
            merged[key] = nextVal;
          }
        };
    for (var i = 0; i < sources.length; i++) {
      Collection(sources[i]).forEach(mergeItem);
    }
    return merged;
  }

  function deepMergerWith(merger) {
    function deepMerger(oldValue, newValue, key) {
      return isDataStructure(oldValue) &&
        isDataStructure(newValue) &&
        areMergeable(oldValue, newValue)
        ? mergeWithSources(oldValue, [newValue], deepMerger)
        : merger
        ? merger(oldValue, newValue, key)
        : newValue;
    }
    return deepMerger;
  }

  /**
   * It's unclear what the desired behavior is for merging two collections that
   * fall into separate categories between keyed, indexed, or set-like, so we only
   * consider them mergeable if they fall into the same category.
   */
  function areMergeable(oldDataStructure, newDataStructure) {
    var oldSeq = Seq(oldDataStructure);
    var newSeq = Seq(newDataStructure);
    // This logic assumes that a sequence can only fall into one of the three
    // categories mentioned above (since there's no `isSetLike()` method).
    return (
      isIndexed(oldSeq) === isIndexed(newSeq) &&
      isKeyed(oldSeq) === isKeyed(newSeq)
    );
  }

  function mergeDeep() {
    var iters = [], len = arguments.length;
    while ( len-- ) iters[ len ] = arguments[ len ];

    return mergeDeepWithSources(this, iters);
  }

  function mergeDeepWith(merger) {
    var iters = [], len = arguments.length - 1;
    while ( len-- > 0 ) iters[ len ] = arguments[ len + 1 ];

    return mergeDeepWithSources(this, iters, merger);
  }

  function mergeIn(keyPath) {
    var iters = [], len = arguments.length - 1;
    while ( len-- > 0 ) iters[ len ] = arguments[ len + 1 ];

    return updateIn$1(this, keyPath, emptyMap(), function (m) { return mergeWithSources(m, iters); });
  }

  function mergeDeepIn(keyPath) {
    var iters = [], len = arguments.length - 1;
    while ( len-- > 0 ) iters[ len ] = arguments[ len + 1 ];

    return updateIn$1(this, keyPath, emptyMap(), function (m) { return mergeDeepWithSources(m, iters); }
    );
  }

  function withMutations(fn) {
    var mutable = this.asMutable();
    fn(mutable);
    return mutable.wasAltered() ? mutable.__ensureOwner(this.__ownerID) : this;
  }

  function asMutable() {
    return this.__ownerID ? this : this.__ensureOwner(new OwnerID());
  }

  function asImmutable() {
    return this.__ensureOwner();
  }

  function wasAltered() {
    return this.__altered;
  }

  var Map = /*@__PURE__*/(function (KeyedCollection) {
    function Map(value) {
      return value === null || value === undefined
        ? emptyMap()
        : isMap(value) && !isOrdered(value)
        ? value
        : emptyMap().withMutations(function (map) {
            var iter = KeyedCollection(value);
            assertNotInfinite(iter.size);
            iter.forEach(function (v, k) { return map.set(k, v); });
          });
    }

    if ( KeyedCollection ) Map.__proto__ = KeyedCollection;
    Map.prototype = Object.create( KeyedCollection && KeyedCollection.prototype );
    Map.prototype.constructor = Map;

    Map.of = function of () {
      var keyValues = [], len = arguments.length;
      while ( len-- ) keyValues[ len ] = arguments[ len ];

      return emptyMap().withMutations(function (map) {
        for (var i = 0; i < keyValues.length; i += 2) {
          if (i + 1 >= keyValues.length) {
            throw new Error('Missing value for key: ' + keyValues[i]);
          }
          map.set(keyValues[i], keyValues[i + 1]);
        }
      });
    };

    Map.prototype.toString = function toString () {
      return this.__toString('Map {', '}');
    };

    // @pragma Access

    Map.prototype.get = function get (k, notSetValue) {
      return this._root
        ? this._root.get(0, undefined, k, notSetValue)
        : notSetValue;
    };

    // @pragma Modification

    Map.prototype.set = function set (k, v) {
      return updateMap(this, k, v);
    };

    Map.prototype.remove = function remove (k) {
      return updateMap(this, k, NOT_SET);
    };

    Map.prototype.deleteAll = function deleteAll (keys) {
      var collection = Collection(keys);

      if (collection.size === 0) {
        return this;
      }

      return this.withMutations(function (map) {
        collection.forEach(function (key) { return map.remove(key); });
      });
    };

    Map.prototype.clear = function clear () {
      if (this.size === 0) {
        return this;
      }
      if (this.__ownerID) {
        this.size = 0;
        this._root = null;
        this.__hash = undefined;
        this.__altered = true;
        return this;
      }
      return emptyMap();
    };

    // @pragma Composition

    Map.prototype.sort = function sort (comparator) {
      // Late binding
      return OrderedMap(sortFactory(this, comparator));
    };

    Map.prototype.sortBy = function sortBy (mapper, comparator) {
      // Late binding
      return OrderedMap(sortFactory(this, comparator, mapper));
    };

    Map.prototype.map = function map (mapper, context) {
      var this$1$1 = this;

      return this.withMutations(function (map) {
        map.forEach(function (value, key) {
          map.set(key, mapper.call(context, value, key, this$1$1));
        });
      });
    };

    // @pragma Mutability

    Map.prototype.__iterator = function __iterator (type, reverse) {
      return new MapIterator(this, type, reverse);
    };

    Map.prototype.__iterate = function __iterate (fn, reverse) {
      var this$1$1 = this;

      var iterations = 0;
      this._root &&
        this._root.iterate(function (entry) {
          iterations++;
          return fn(entry[1], entry[0], this$1$1);
        }, reverse);
      return iterations;
    };

    Map.prototype.__ensureOwner = function __ensureOwner (ownerID) {
      if (ownerID === this.__ownerID) {
        return this;
      }
      if (!ownerID) {
        if (this.size === 0) {
          return emptyMap();
        }
        this.__ownerID = ownerID;
        this.__altered = false;
        return this;
      }
      return makeMap(this.size, this._root, ownerID, this.__hash);
    };

    return Map;
  }(KeyedCollection));

  Map.isMap = isMap;

  var MapPrototype = Map.prototype;
  MapPrototype[IS_MAP_SYMBOL] = true;
  MapPrototype[DELETE] = MapPrototype.remove;
  MapPrototype.removeAll = MapPrototype.deleteAll;
  MapPrototype.setIn = setIn;
  MapPrototype.removeIn = MapPrototype.deleteIn = deleteIn;
  MapPrototype.update = update;
  MapPrototype.updateIn = updateIn;
  MapPrototype.merge = MapPrototype.concat = merge$1;
  MapPrototype.mergeWith = mergeWith$1;
  MapPrototype.mergeDeep = mergeDeep;
  MapPrototype.mergeDeepWith = mergeDeepWith;
  MapPrototype.mergeIn = mergeIn;
  MapPrototype.mergeDeepIn = mergeDeepIn;
  MapPrototype.withMutations = withMutations;
  MapPrototype.wasAltered = wasAltered;
  MapPrototype.asImmutable = asImmutable;
  MapPrototype['@@transducer/init'] = MapPrototype.asMutable = asMutable;
  MapPrototype['@@transducer/step'] = function (result, arr) {
    return result.set(arr[0], arr[1]);
  };
  MapPrototype['@@transducer/result'] = function (obj) {
    return obj.asImmutable();
  };

  // #pragma Trie Nodes

  var ArrayMapNode = function ArrayMapNode(ownerID, entries) {
    this.ownerID = ownerID;
    this.entries = entries;
  };

  ArrayMapNode.prototype.get = function get (shift, keyHash, key, notSetValue) {
    var entries = this.entries;
    for (var ii = 0, len = entries.length; ii < len; ii++) {
      if (is(key, entries[ii][0])) {
        return entries[ii][1];
      }
    }
    return notSetValue;
  };

  ArrayMapNode.prototype.update = function update (ownerID, shift, keyHash, key, value, didChangeSize, didAlter) {
    var removed = value === NOT_SET;

    var entries = this.entries;
    var idx = 0;
    var len = entries.length;
    for (; idx < len; idx++) {
      if (is(key, entries[idx][0])) {
        break;
      }
    }
    var exists = idx < len;

    if (exists ? entries[idx][1] === value : removed) {
      return this;
    }

    SetRef(didAlter);
    (removed || !exists) && SetRef(didChangeSize);

    if (removed && entries.length === 1) {
      return; // undefined
    }

    if (!exists && !removed && entries.length >= MAX_ARRAY_MAP_SIZE) {
      return createNodes(ownerID, entries, key, value);
    }

    var isEditable = ownerID && ownerID === this.ownerID;
    var newEntries = isEditable ? entries : arrCopy(entries);

    if (exists) {
      if (removed) {
        idx === len - 1
          ? newEntries.pop()
          : (newEntries[idx] = newEntries.pop());
      } else {
        newEntries[idx] = [key, value];
      }
    } else {
      newEntries.push([key, value]);
    }

    if (isEditable) {
      this.entries = newEntries;
      return this;
    }

    return new ArrayMapNode(ownerID, newEntries);
  };

  var BitmapIndexedNode = function BitmapIndexedNode(ownerID, bitmap, nodes) {
    this.ownerID = ownerID;
    this.bitmap = bitmap;
    this.nodes = nodes;
  };

  BitmapIndexedNode.prototype.get = function get (shift, keyHash, key, notSetValue) {
    if (keyHash === undefined) {
      keyHash = hash(key);
    }
    var bit = 1 << ((shift === 0 ? keyHash : keyHash >>> shift) & MASK);
    var bitmap = this.bitmap;
    return (bitmap & bit) === 0
      ? notSetValue
      : this.nodes[popCount(bitmap & (bit - 1))].get(
          shift + SHIFT,
          keyHash,
          key,
          notSetValue
        );
  };

  BitmapIndexedNode.prototype.update = function update (ownerID, shift, keyHash, key, value, didChangeSize, didAlter) {
    if (keyHash === undefined) {
      keyHash = hash(key);
    }
    var keyHashFrag = (shift === 0 ? keyHash : keyHash >>> shift) & MASK;
    var bit = 1 << keyHashFrag;
    var bitmap = this.bitmap;
    var exists = (bitmap & bit) !== 0;

    if (!exists && value === NOT_SET) {
      return this;
    }

    var idx = popCount(bitmap & (bit - 1));
    var nodes = this.nodes;
    var node = exists ? nodes[idx] : undefined;
    var newNode = updateNode(
      node,
      ownerID,
      shift + SHIFT,
      keyHash,
      key,
      value,
      didChangeSize,
      didAlter
    );

    if (newNode === node) {
      return this;
    }

    if (!exists && newNode && nodes.length >= MAX_BITMAP_INDEXED_SIZE) {
      return expandNodes(ownerID, nodes, bitmap, keyHashFrag, newNode);
    }

    if (
      exists &&
      !newNode &&
      nodes.length === 2 &&
      isLeafNode(nodes[idx ^ 1])
    ) {
      return nodes[idx ^ 1];
    }

    if (exists && newNode && nodes.length === 1 && isLeafNode(newNode)) {
      return newNode;
    }

    var isEditable = ownerID && ownerID === this.ownerID;
    var newBitmap = exists ? (newNode ? bitmap : bitmap ^ bit) : bitmap | bit;
    var newNodes = exists
      ? newNode
        ? setAt(nodes, idx, newNode, isEditable)
        : spliceOut(nodes, idx, isEditable)
      : spliceIn(nodes, idx, newNode, isEditable);

    if (isEditable) {
      this.bitmap = newBitmap;
      this.nodes = newNodes;
      return this;
    }

    return new BitmapIndexedNode(ownerID, newBitmap, newNodes);
  };

  var HashArrayMapNode = function HashArrayMapNode(ownerID, count, nodes) {
    this.ownerID = ownerID;
    this.count = count;
    this.nodes = nodes;
  };

  HashArrayMapNode.prototype.get = function get (shift, keyHash, key, notSetValue) {
    if (keyHash === undefined) {
      keyHash = hash(key);
    }
    var idx = (shift === 0 ? keyHash : keyHash >>> shift) & MASK;
    var node = this.nodes[idx];
    return node
      ? node.get(shift + SHIFT, keyHash, key, notSetValue)
      : notSetValue;
  };

  HashArrayMapNode.prototype.update = function update (ownerID, shift, keyHash, key, value, didChangeSize, didAlter) {
    if (keyHash === undefined) {
      keyHash = hash(key);
    }
    var idx = (shift === 0 ? keyHash : keyHash >>> shift) & MASK;
    var removed = value === NOT_SET;
    var nodes = this.nodes;
    var node = nodes[idx];

    if (removed && !node) {
      return this;
    }

    var newNode = updateNode(
      node,
      ownerID,
      shift + SHIFT,
      keyHash,
      key,
      value,
      didChangeSize,
      didAlter
    );
    if (newNode === node) {
      return this;
    }

    var newCount = this.count;
    if (!node) {
      newCount++;
    } else if (!newNode) {
      newCount--;
      if (newCount < MIN_HASH_ARRAY_MAP_SIZE) {
        return packNodes(ownerID, nodes, newCount, idx);
      }
    }

    var isEditable = ownerID && ownerID === this.ownerID;
    var newNodes = setAt(nodes, idx, newNode, isEditable);

    if (isEditable) {
      this.count = newCount;
      this.nodes = newNodes;
      return this;
    }

    return new HashArrayMapNode(ownerID, newCount, newNodes);
  };

  var HashCollisionNode = function HashCollisionNode(ownerID, keyHash, entries) {
    this.ownerID = ownerID;
    this.keyHash = keyHash;
    this.entries = entries;
  };

  HashCollisionNode.prototype.get = function get (shift, keyHash, key, notSetValue) {
    var entries = this.entries;
    for (var ii = 0, len = entries.length; ii < len; ii++) {
      if (is(key, entries[ii][0])) {
        return entries[ii][1];
      }
    }
    return notSetValue;
  };

  HashCollisionNode.prototype.update = function update (ownerID, shift, keyHash, key, value, didChangeSize, didAlter) {
    if (keyHash === undefined) {
      keyHash = hash(key);
    }

    var removed = value === NOT_SET;

    if (keyHash !== this.keyHash) {
      if (removed) {
        return this;
      }
      SetRef(didAlter);
      SetRef(didChangeSize);
      return mergeIntoNode(this, ownerID, shift, keyHash, [key, value]);
    }

    var entries = this.entries;
    var idx = 0;
    var len = entries.length;
    for (; idx < len; idx++) {
      if (is(key, entries[idx][0])) {
        break;
      }
    }
    var exists = idx < len;

    if (exists ? entries[idx][1] === value : removed) {
      return this;
    }

    SetRef(didAlter);
    (removed || !exists) && SetRef(didChangeSize);

    if (removed && len === 2) {
      return new ValueNode(ownerID, this.keyHash, entries[idx ^ 1]);
    }

    var isEditable = ownerID && ownerID === this.ownerID;
    var newEntries = isEditable ? entries : arrCopy(entries);

    if (exists) {
      if (removed) {
        idx === len - 1
          ? newEntries.pop()
          : (newEntries[idx] = newEntries.pop());
      } else {
        newEntries[idx] = [key, value];
      }
    } else {
      newEntries.push([key, value]);
    }

    if (isEditable) {
      this.entries = newEntries;
      return this;
    }

    return new HashCollisionNode(ownerID, this.keyHash, newEntries);
  };

  var ValueNode = function ValueNode(ownerID, keyHash, entry) {
    this.ownerID = ownerID;
    this.keyHash = keyHash;
    this.entry = entry;
  };

  ValueNode.prototype.get = function get (shift, keyHash, key, notSetValue) {
    return is(key, this.entry[0]) ? this.entry[1] : notSetValue;
  };

  ValueNode.prototype.update = function update (ownerID, shift, keyHash, key, value, didChangeSize, didAlter) {
    var removed = value === NOT_SET;
    var keyMatch = is(key, this.entry[0]);
    if (keyMatch ? value === this.entry[1] : removed) {
      return this;
    }

    SetRef(didAlter);

    if (removed) {
      SetRef(didChangeSize);
      return; // undefined
    }

    if (keyMatch) {
      if (ownerID && ownerID === this.ownerID) {
        this.entry[1] = value;
        return this;
      }
      return new ValueNode(ownerID, this.keyHash, [key, value]);
    }

    SetRef(didChangeSize);
    return mergeIntoNode(this, ownerID, shift, hash(key), [key, value]);
  };

  // #pragma Iterators

  ArrayMapNode.prototype.iterate = HashCollisionNode.prototype.iterate =
    function (fn, reverse) {
      var entries = this.entries;
      for (var ii = 0, maxIndex = entries.length - 1; ii <= maxIndex; ii++) {
        if (fn(entries[reverse ? maxIndex - ii : ii]) === false) {
          return false;
        }
      }
    };

  BitmapIndexedNode.prototype.iterate = HashArrayMapNode.prototype.iterate =
    function (fn, reverse) {
      var nodes = this.nodes;
      for (var ii = 0, maxIndex = nodes.length - 1; ii <= maxIndex; ii++) {
        var node = nodes[reverse ? maxIndex - ii : ii];
        if (node && node.iterate(fn, reverse) === false) {
          return false;
        }
      }
    };

  // eslint-disable-next-line no-unused-vars
  ValueNode.prototype.iterate = function (fn, reverse) {
    return fn(this.entry);
  };

  var MapIterator = /*@__PURE__*/(function (Iterator) {
    function MapIterator(map, type, reverse) {
      this._type = type;
      this._reverse = reverse;
      this._stack = map._root && mapIteratorFrame(map._root);
    }

    if ( Iterator ) MapIterator.__proto__ = Iterator;
    MapIterator.prototype = Object.create( Iterator && Iterator.prototype );
    MapIterator.prototype.constructor = MapIterator;

    MapIterator.prototype.next = function next () {
      var type = this._type;
      var stack = this._stack;
      while (stack) {
        var node = stack.node;
        var index = stack.index++;
        var maxIndex = (void 0);
        if (node.entry) {
          if (index === 0) {
            return mapIteratorValue(type, node.entry);
          }
        } else if (node.entries) {
          maxIndex = node.entries.length - 1;
          if (index <= maxIndex) {
            return mapIteratorValue(
              type,
              node.entries[this._reverse ? maxIndex - index : index]
            );
          }
        } else {
          maxIndex = node.nodes.length - 1;
          if (index <= maxIndex) {
            var subNode = node.nodes[this._reverse ? maxIndex - index : index];
            if (subNode) {
              if (subNode.entry) {
                return mapIteratorValue(type, subNode.entry);
              }
              stack = this._stack = mapIteratorFrame(subNode, stack);
            }
            continue;
          }
        }
        stack = this._stack = this._stack.__prev;
      }
      return iteratorDone();
    };

    return MapIterator;
  }(Iterator));

  function mapIteratorValue(type, entry) {
    return iteratorValue(type, entry[0], entry[1]);
  }

  function mapIteratorFrame(node, prev) {
    return {
      node: node,
      index: 0,
      __prev: prev,
    };
  }

  function makeMap(size, root, ownerID, hash) {
    var map = Object.create(MapPrototype);
    map.size = size;
    map._root = root;
    map.__ownerID = ownerID;
    map.__hash = hash;
    map.__altered = false;
    return map;
  }

  var EMPTY_MAP;
  function emptyMap() {
    return EMPTY_MAP || (EMPTY_MAP = makeMap(0));
  }

  function updateMap(map, k, v) {
    var newRoot;
    var newSize;
    if (!map._root) {
      if (v === NOT_SET) {
        return map;
      }
      newSize = 1;
      newRoot = new ArrayMapNode(map.__ownerID, [[k, v]]);
    } else {
      var didChangeSize = MakeRef();
      var didAlter = MakeRef();
      newRoot = updateNode(
        map._root,
        map.__ownerID,
        0,
        undefined,
        k,
        v,
        didChangeSize,
        didAlter
      );
      if (!didAlter.value) {
        return map;
      }
      newSize = map.size + (didChangeSize.value ? (v === NOT_SET ? -1 : 1) : 0);
    }
    if (map.__ownerID) {
      map.size = newSize;
      map._root = newRoot;
      map.__hash = undefined;
      map.__altered = true;
      return map;
    }
    return newRoot ? makeMap(newSize, newRoot) : emptyMap();
  }

  function updateNode(
    node,
    ownerID,
    shift,
    keyHash,
    key,
    value,
    didChangeSize,
    didAlter
  ) {
    if (!node) {
      if (value === NOT_SET) {
        return node;
      }
      SetRef(didAlter);
      SetRef(didChangeSize);
      return new ValueNode(ownerID, keyHash, [key, value]);
    }
    return node.update(
      ownerID,
      shift,
      keyHash,
      key,
      value,
      didChangeSize,
      didAlter
    );
  }

  function isLeafNode(node) {
    return (
      node.constructor === ValueNode || node.constructor === HashCollisionNode
    );
  }

  function mergeIntoNode(node, ownerID, shift, keyHash, entry) {
    if (node.keyHash === keyHash) {
      return new HashCollisionNode(ownerID, keyHash, [node.entry, entry]);
    }

    var idx1 = (shift === 0 ? node.keyHash : node.keyHash >>> shift) & MASK;
    var idx2 = (shift === 0 ? keyHash : keyHash >>> shift) & MASK;

    var newNode;
    var nodes =
      idx1 === idx2
        ? [mergeIntoNode(node, ownerID, shift + SHIFT, keyHash, entry)]
        : ((newNode = new ValueNode(ownerID, keyHash, entry)),
          idx1 < idx2 ? [node, newNode] : [newNode, node]);

    return new BitmapIndexedNode(ownerID, (1 << idx1) | (1 << idx2), nodes);
  }

  function createNodes(ownerID, entries, key, value) {
    if (!ownerID) {
      ownerID = new OwnerID();
    }
    var node = new ValueNode(ownerID, hash(key), [key, value]);
    for (var ii = 0; ii < entries.length; ii++) {
      var entry = entries[ii];
      node = node.update(ownerID, 0, undefined, entry[0], entry[1]);
    }
    return node;
  }

  function packNodes(ownerID, nodes, count, excluding) {
    var bitmap = 0;
    var packedII = 0;
    var packedNodes = new Array(count);
    for (var ii = 0, bit = 1, len = nodes.length; ii < len; ii++, bit <<= 1) {
      var node = nodes[ii];
      if (node !== undefined && ii !== excluding) {
        bitmap |= bit;
        packedNodes[packedII++] = node;
      }
    }
    return new BitmapIndexedNode(ownerID, bitmap, packedNodes);
  }

  function expandNodes(ownerID, nodes, bitmap, including, node) {
    var count = 0;
    var expandedNodes = new Array(SIZE);
    for (var ii = 0; bitmap !== 0; ii++, bitmap >>>= 1) {
      expandedNodes[ii] = bitmap & 1 ? nodes[count++] : undefined;
    }
    expandedNodes[including] = node;
    return new HashArrayMapNode(ownerID, count + 1, expandedNodes);
  }

  function popCount(x) {
    x -= (x >> 1) & 0x55555555;
    x = (x & 0x33333333) + ((x >> 2) & 0x33333333);
    x = (x + (x >> 4)) & 0x0f0f0f0f;
    x += x >> 8;
    x += x >> 16;
    return x & 0x7f;
  }

  function setAt(array, idx, val, canEdit) {
    var newArray = canEdit ? array : arrCopy(array);
    newArray[idx] = val;
    return newArray;
  }

  function spliceIn(array, idx, val, canEdit) {
    var newLen = array.length + 1;
    if (canEdit && idx + 1 === newLen) {
      array[idx] = val;
      return array;
    }
    var newArray = new Array(newLen);
    var after = 0;
    for (var ii = 0; ii < newLen; ii++) {
      if (ii === idx) {
        newArray[ii] = val;
        after = -1;
      } else {
        newArray[ii] = array[ii + after];
      }
    }
    return newArray;
  }

  function spliceOut(array, idx, canEdit) {
    var newLen = array.length - 1;
    if (canEdit && idx === newLen) {
      array.pop();
      return array;
    }
    var newArray = new Array(newLen);
    var after = 0;
    for (var ii = 0; ii < newLen; ii++) {
      if (ii === idx) {
        after = 1;
      }
      newArray[ii] = array[ii + after];
    }
    return newArray;
  }

  var MAX_ARRAY_MAP_SIZE = SIZE / 4;
  var MAX_BITMAP_INDEXED_SIZE = SIZE / 2;
  var MIN_HASH_ARRAY_MAP_SIZE = SIZE / 4;

  var IS_LIST_SYMBOL = '@@__IMMUTABLE_LIST__@@';

  function isList(maybeList) {
    return Boolean(maybeList && maybeList[IS_LIST_SYMBOL]);
  }

  var List = /*@__PURE__*/(function (IndexedCollection) {
    function List(value) {
      var empty = emptyList();
      if (value === null || value === undefined) {
        return empty;
      }
      if (isList(value)) {
        return value;
      }
      var iter = IndexedCollection(value);
      var size = iter.size;
      if (size === 0) {
        return empty;
      }
      assertNotInfinite(size);
      if (size > 0 && size < SIZE) {
        return makeList(0, size, SHIFT, null, new VNode(iter.toArray()));
      }
      return empty.withMutations(function (list) {
        list.setSize(size);
        iter.forEach(function (v, i) { return list.set(i, v); });
      });
    }

    if ( IndexedCollection ) List.__proto__ = IndexedCollection;
    List.prototype = Object.create( IndexedCollection && IndexedCollection.prototype );
    List.prototype.constructor = List;

    List.of = function of (/*...values*/) {
      return this(arguments);
    };

    List.prototype.toString = function toString () {
      return this.__toString('List [', ']');
    };

    // @pragma Access

    List.prototype.get = function get (index, notSetValue) {
      index = wrapIndex(this, index);
      if (index >= 0 && index < this.size) {
        index += this._origin;
        var node = listNodeFor(this, index);
        return node && node.array[index & MASK];
      }
      return notSetValue;
    };

    // @pragma Modification

    List.prototype.set = function set (index, value) {
      return updateList(this, index, value);
    };

    List.prototype.remove = function remove (index) {
      return !this.has(index)
        ? this
        : index === 0
        ? this.shift()
        : index === this.size - 1
        ? this.pop()
        : this.splice(index, 1);
    };

    List.prototype.insert = function insert (index, value) {
      return this.splice(index, 0, value);
    };

    List.prototype.clear = function clear () {
      if (this.size === 0) {
        return this;
      }
      if (this.__ownerID) {
        this.size = this._origin = this._capacity = 0;
        this._level = SHIFT;
        this._root = this._tail = this.__hash = undefined;
        this.__altered = true;
        return this;
      }
      return emptyList();
    };

    List.prototype.push = function push (/*...values*/) {
      var values = arguments;
      var oldSize = this.size;
      return this.withMutations(function (list) {
        setListBounds(list, 0, oldSize + values.length);
        for (var ii = 0; ii < values.length; ii++) {
          list.set(oldSize + ii, values[ii]);
        }
      });
    };

    List.prototype.pop = function pop () {
      return setListBounds(this, 0, -1);
    };

    List.prototype.unshift = function unshift (/*...values*/) {
      var values = arguments;
      return this.withMutations(function (list) {
        setListBounds(list, -values.length);
        for (var ii = 0; ii < values.length; ii++) {
          list.set(ii, values[ii]);
        }
      });
    };

    List.prototype.shift = function shift () {
      return setListBounds(this, 1);
    };

    // @pragma Composition

    List.prototype.concat = function concat (/*...collections*/) {
      var arguments$1 = arguments;

      var seqs = [];
      for (var i = 0; i < arguments.length; i++) {
        var argument = arguments$1[i];
        var seq = IndexedCollection(
          typeof argument !== 'string' && hasIterator(argument)
            ? argument
            : [argument]
        );
        if (seq.size !== 0) {
          seqs.push(seq);
        }
      }
      if (seqs.length === 0) {
        return this;
      }
      if (this.size === 0 && !this.__ownerID && seqs.length === 1) {
        return this.constructor(seqs[0]);
      }
      return this.withMutations(function (list) {
        seqs.forEach(function (seq) { return seq.forEach(function (value) { return list.push(value); }); });
      });
    };

    List.prototype.setSize = function setSize (size) {
      return setListBounds(this, 0, size);
    };

    List.prototype.map = function map (mapper, context) {
      var this$1$1 = this;

      return this.withMutations(function (list) {
        for (var i = 0; i < this$1$1.size; i++) {
          list.set(i, mapper.call(context, list.get(i), i, this$1$1));
        }
      });
    };

    // @pragma Iteration

    List.prototype.slice = function slice (begin, end) {
      var size = this.size;
      if (wholeSlice(begin, end, size)) {
        return this;
      }
      return setListBounds(
        this,
        resolveBegin(begin, size),
        resolveEnd(end, size)
      );
    };

    List.prototype.__iterator = function __iterator (type, reverse) {
      var index = reverse ? this.size : 0;
      var values = iterateList(this, reverse);
      return new Iterator(function () {
        var value = values();
        return value === DONE
          ? iteratorDone()
          : iteratorValue(type, reverse ? --index : index++, value);
      });
    };

    List.prototype.__iterate = function __iterate (fn, reverse) {
      var index = reverse ? this.size : 0;
      var values = iterateList(this, reverse);
      var value;
      while ((value = values()) !== DONE) {
        if (fn(value, reverse ? --index : index++, this) === false) {
          break;
        }
      }
      return index;
    };

    List.prototype.__ensureOwner = function __ensureOwner (ownerID) {
      if (ownerID === this.__ownerID) {
        return this;
      }
      if (!ownerID) {
        if (this.size === 0) {
          return emptyList();
        }
        this.__ownerID = ownerID;
        this.__altered = false;
        return this;
      }
      return makeList(
        this._origin,
        this._capacity,
        this._level,
        this._root,
        this._tail,
        ownerID,
        this.__hash
      );
    };

    return List;
  }(IndexedCollection));

  List.isList = isList;

  var ListPrototype = List.prototype;
  ListPrototype[IS_LIST_SYMBOL] = true;
  ListPrototype[DELETE] = ListPrototype.remove;
  ListPrototype.merge = ListPrototype.concat;
  ListPrototype.setIn = setIn;
  ListPrototype.deleteIn = ListPrototype.removeIn = deleteIn;
  ListPrototype.update = update;
  ListPrototype.updateIn = updateIn;
  ListPrototype.mergeIn = mergeIn;
  ListPrototype.mergeDeepIn = mergeDeepIn;
  ListPrototype.withMutations = withMutations;
  ListPrototype.wasAltered = wasAltered;
  ListPrototype.asImmutable = asImmutable;
  ListPrototype['@@transducer/init'] = ListPrototype.asMutable = asMutable;
  ListPrototype['@@transducer/step'] = function (result, arr) {
    return result.push(arr);
  };
  ListPrototype['@@transducer/result'] = function (obj) {
    return obj.asImmutable();
  };

  var VNode = function VNode(array, ownerID) {
    this.array = array;
    this.ownerID = ownerID;
  };

  // TODO: seems like these methods are very similar

  VNode.prototype.removeBefore = function removeBefore (ownerID, level, index) {
    if (index === level ? 1 << level : this.array.length === 0) {
      return this;
    }
    var originIndex = (index >>> level) & MASK;
    if (originIndex >= this.array.length) {
      return new VNode([], ownerID);
    }
    var removingFirst = originIndex === 0;
    var newChild;
    if (level > 0) {
      var oldChild = this.array[originIndex];
      newChild =
        oldChild && oldChild.removeBefore(ownerID, level - SHIFT, index);
      if (newChild === oldChild && removingFirst) {
        return this;
      }
    }
    if (removingFirst && !newChild) {
      return this;
    }
    var editable = editableVNode(this, ownerID);
    if (!removingFirst) {
      for (var ii = 0; ii < originIndex; ii++) {
        editable.array[ii] = undefined;
      }
    }
    if (newChild) {
      editable.array[originIndex] = newChild;
    }
    return editable;
  };

  VNode.prototype.removeAfter = function removeAfter (ownerID, level, index) {
    if (index === (level ? 1 << level : 0) || this.array.length === 0) {
      return this;
    }
    var sizeIndex = ((index - 1) >>> level) & MASK;
    if (sizeIndex >= this.array.length) {
      return this;
    }

    var newChild;
    if (level > 0) {
      var oldChild = this.array[sizeIndex];
      newChild =
        oldChild && oldChild.removeAfter(ownerID, level - SHIFT, index);
      if (newChild === oldChild && sizeIndex === this.array.length - 1) {
        return this;
      }
    }

    var editable = editableVNode(this, ownerID);
    editable.array.splice(sizeIndex + 1);
    if (newChild) {
      editable.array[sizeIndex] = newChild;
    }
    return editable;
  };

  var DONE = {};

  function iterateList(list, reverse) {
    var left = list._origin;
    var right = list._capacity;
    var tailPos = getTailOffset(right);
    var tail = list._tail;

    return iterateNodeOrLeaf(list._root, list._level, 0);

    function iterateNodeOrLeaf(node, level, offset) {
      return level === 0
        ? iterateLeaf(node, offset)
        : iterateNode(node, level, offset);
    }

    function iterateLeaf(node, offset) {
      var array = offset === tailPos ? tail && tail.array : node && node.array;
      var from = offset > left ? 0 : left - offset;
      var to = right - offset;
      if (to > SIZE) {
        to = SIZE;
      }
      return function () {
        if (from === to) {
          return DONE;
        }
        var idx = reverse ? --to : from++;
        return array && array[idx];
      };
    }

    function iterateNode(node, level, offset) {
      var values;
      var array = node && node.array;
      var from = offset > left ? 0 : (left - offset) >> level;
      var to = ((right - offset) >> level) + 1;
      if (to > SIZE) {
        to = SIZE;
      }
      return function () {
        while (true) {
          if (values) {
            var value = values();
            if (value !== DONE) {
              return value;
            }
            values = null;
          }
          if (from === to) {
            return DONE;
          }
          var idx = reverse ? --to : from++;
          values = iterateNodeOrLeaf(
            array && array[idx],
            level - SHIFT,
            offset + (idx << level)
          );
        }
      };
    }
  }

  function makeList(origin, capacity, level, root, tail, ownerID, hash) {
    var list = Object.create(ListPrototype);
    list.size = capacity - origin;
    list._origin = origin;
    list._capacity = capacity;
    list._level = level;
    list._root = root;
    list._tail = tail;
    list.__ownerID = ownerID;
    list.__hash = hash;
    list.__altered = false;
    return list;
  }

  var EMPTY_LIST;
  function emptyList() {
    return EMPTY_LIST || (EMPTY_LIST = makeList(0, 0, SHIFT));
  }

  function updateList(list, index, value) {
    index = wrapIndex(list, index);

    if (index !== index) {
      return list;
    }

    if (index >= list.size || index < 0) {
      return list.withMutations(function (list) {
        index < 0
          ? setListBounds(list, index).set(0, value)
          : setListBounds(list, 0, index + 1).set(index, value);
      });
    }

    index += list._origin;

    var newTail = list._tail;
    var newRoot = list._root;
    var didAlter = MakeRef();
    if (index >= getTailOffset(list._capacity)) {
      newTail = updateVNode(newTail, list.__ownerID, 0, index, value, didAlter);
    } else {
      newRoot = updateVNode(
        newRoot,
        list.__ownerID,
        list._level,
        index,
        value,
        didAlter
      );
    }

    if (!didAlter.value) {
      return list;
    }

    if (list.__ownerID) {
      list._root = newRoot;
      list._tail = newTail;
      list.__hash = undefined;
      list.__altered = true;
      return list;
    }
    return makeList(list._origin, list._capacity, list._level, newRoot, newTail);
  }

  function updateVNode(node, ownerID, level, index, value, didAlter) {
    var idx = (index >>> level) & MASK;
    var nodeHas = node && idx < node.array.length;
    if (!nodeHas && value === undefined) {
      return node;
    }

    var newNode;

    if (level > 0) {
      var lowerNode = node && node.array[idx];
      var newLowerNode = updateVNode(
        lowerNode,
        ownerID,
        level - SHIFT,
        index,
        value,
        didAlter
      );
      if (newLowerNode === lowerNode) {
        return node;
      }
      newNode = editableVNode(node, ownerID);
      newNode.array[idx] = newLowerNode;
      return newNode;
    }

    if (nodeHas && node.array[idx] === value) {
      return node;
    }

    if (didAlter) {
      SetRef(didAlter);
    }

    newNode = editableVNode(node, ownerID);
    if (value === undefined && idx === newNode.array.length - 1) {
      newNode.array.pop();
    } else {
      newNode.array[idx] = value;
    }
    return newNode;
  }

  function editableVNode(node, ownerID) {
    if (ownerID && node && ownerID === node.ownerID) {
      return node;
    }
    return new VNode(node ? node.array.slice() : [], ownerID);
  }

  function listNodeFor(list, rawIndex) {
    if (rawIndex >= getTailOffset(list._capacity)) {
      return list._tail;
    }
    if (rawIndex < 1 << (list._level + SHIFT)) {
      var node = list._root;
      var level = list._level;
      while (node && level > 0) {
        node = node.array[(rawIndex >>> level) & MASK];
        level -= SHIFT;
      }
      return node;
    }
  }

  function setListBounds(list, begin, end) {
    // Sanitize begin & end using this shorthand for ToInt32(argument)
    // http://www.ecma-international.org/ecma-262/6.0/#sec-toint32
    if (begin !== undefined) {
      begin |= 0;
    }
    if (end !== undefined) {
      end |= 0;
    }
    var owner = list.__ownerID || new OwnerID();
    var oldOrigin = list._origin;
    var oldCapacity = list._capacity;
    var newOrigin = oldOrigin + begin;
    var newCapacity =
      end === undefined
        ? oldCapacity
        : end < 0
        ? oldCapacity + end
        : oldOrigin + end;
    if (newOrigin === oldOrigin && newCapacity === oldCapacity) {
      return list;
    }

    // If it's going to end after it starts, it's empty.
    if (newOrigin >= newCapacity) {
      return list.clear();
    }

    var newLevel = list._level;
    var newRoot = list._root;

    // New origin might need creating a higher root.
    var offsetShift = 0;
    while (newOrigin + offsetShift < 0) {
      newRoot = new VNode(
        newRoot && newRoot.array.length ? [undefined, newRoot] : [],
        owner
      );
      newLevel += SHIFT;
      offsetShift += 1 << newLevel;
    }
    if (offsetShift) {
      newOrigin += offsetShift;
      oldOrigin += offsetShift;
      newCapacity += offsetShift;
      oldCapacity += offsetShift;
    }

    var oldTailOffset = getTailOffset(oldCapacity);
    var newTailOffset = getTailOffset(newCapacity);

    // New size might need creating a higher root.
    while (newTailOffset >= 1 << (newLevel + SHIFT)) {
      newRoot = new VNode(
        newRoot && newRoot.array.length ? [newRoot] : [],
        owner
      );
      newLevel += SHIFT;
    }

    // Locate or create the new tail.
    var oldTail = list._tail;
    var newTail =
      newTailOffset < oldTailOffset
        ? listNodeFor(list, newCapacity - 1)
        : newTailOffset > oldTailOffset
        ? new VNode([], owner)
        : oldTail;

    // Merge Tail into tree.
    if (
      oldTail &&
      newTailOffset > oldTailOffset &&
      newOrigin < oldCapacity &&
      oldTail.array.length
    ) {
      newRoot = editableVNode(newRoot, owner);
      var node = newRoot;
      for (var level = newLevel; level > SHIFT; level -= SHIFT) {
        var idx = (oldTailOffset >>> level) & MASK;
        node = node.array[idx] = editableVNode(node.array[idx], owner);
      }
      node.array[(oldTailOffset >>> SHIFT) & MASK] = oldTail;
    }

    // If the size has been reduced, there's a chance the tail needs to be trimmed.
    if (newCapacity < oldCapacity) {
      newTail = newTail && newTail.removeAfter(owner, 0, newCapacity);
    }

    // If the new origin is within the tail, then we do not need a root.
    if (newOrigin >= newTailOffset) {
      newOrigin -= newTailOffset;
      newCapacity -= newTailOffset;
      newLevel = SHIFT;
      newRoot = null;
      newTail = newTail && newTail.removeBefore(owner, 0, newOrigin);

      // Otherwise, if the root has been trimmed, garbage collect.
    } else if (newOrigin > oldOrigin || newTailOffset < oldTailOffset) {
      offsetShift = 0;

      // Identify the new top root node of the subtree of the old root.
      while (newRoot) {
        var beginIndex = (newOrigin >>> newLevel) & MASK;
        if ((beginIndex !== newTailOffset >>> newLevel) & MASK) {
          break;
        }
        if (beginIndex) {
          offsetShift += (1 << newLevel) * beginIndex;
        }
        newLevel -= SHIFT;
        newRoot = newRoot.array[beginIndex];
      }

      // Trim the new sides of the new root.
      if (newRoot && newOrigin > oldOrigin) {
        newRoot = newRoot.removeBefore(owner, newLevel, newOrigin - offsetShift);
      }
      if (newRoot && newTailOffset < oldTailOffset) {
        newRoot = newRoot.removeAfter(
          owner,
          newLevel,
          newTailOffset - offsetShift
        );
      }
      if (offsetShift) {
        newOrigin -= offsetShift;
        newCapacity -= offsetShift;
      }
    }

    if (list.__ownerID) {
      list.size = newCapacity - newOrigin;
      list._origin = newOrigin;
      list._capacity = newCapacity;
      list._level = newLevel;
      list._root = newRoot;
      list._tail = newTail;
      list.__hash = undefined;
      list.__altered = true;
      return list;
    }
    return makeList(newOrigin, newCapacity, newLevel, newRoot, newTail);
  }

  function getTailOffset(size) {
    return size < SIZE ? 0 : ((size - 1) >>> SHIFT) << SHIFT;
  }

  var OrderedMap = /*@__PURE__*/(function (Map) {
    function OrderedMap(value) {
      return value === null || value === undefined
        ? emptyOrderedMap()
        : isOrderedMap(value)
        ? value
        : emptyOrderedMap().withMutations(function (map) {
            var iter = KeyedCollection(value);
            assertNotInfinite(iter.size);
            iter.forEach(function (v, k) { return map.set(k, v); });
          });
    }

    if ( Map ) OrderedMap.__proto__ = Map;
    OrderedMap.prototype = Object.create( Map && Map.prototype );
    OrderedMap.prototype.constructor = OrderedMap;

    OrderedMap.of = function of (/*...values*/) {
      return this(arguments);
    };

    OrderedMap.prototype.toString = function toString () {
      return this.__toString('OrderedMap {', '}');
    };

    // @pragma Access

    OrderedMap.prototype.get = function get (k, notSetValue) {
      var index = this._map.get(k);
      return index !== undefined ? this._list.get(index)[1] : notSetValue;
    };

    // @pragma Modification

    OrderedMap.prototype.clear = function clear () {
      if (this.size === 0) {
        return this;
      }
      if (this.__ownerID) {
        this.size = 0;
        this._map.clear();
        this._list.clear();
        this.__altered = true;
        return this;
      }
      return emptyOrderedMap();
    };

    OrderedMap.prototype.set = function set (k, v) {
      return updateOrderedMap(this, k, v);
    };

    OrderedMap.prototype.remove = function remove (k) {
      return updateOrderedMap(this, k, NOT_SET);
    };

    OrderedMap.prototype.__iterate = function __iterate (fn, reverse) {
      var this$1$1 = this;

      return this._list.__iterate(
        function (entry) { return entry && fn(entry[1], entry[0], this$1$1); },
        reverse
      );
    };

    OrderedMap.prototype.__iterator = function __iterator (type, reverse) {
      return this._list.fromEntrySeq().__iterator(type, reverse);
    };

    OrderedMap.prototype.__ensureOwner = function __ensureOwner (ownerID) {
      if (ownerID === this.__ownerID) {
        return this;
      }
      var newMap = this._map.__ensureOwner(ownerID);
      var newList = this._list.__ensureOwner(ownerID);
      if (!ownerID) {
        if (this.size === 0) {
          return emptyOrderedMap();
        }
        this.__ownerID = ownerID;
        this.__altered = false;
        this._map = newMap;
        this._list = newList;
        return this;
      }
      return makeOrderedMap(newMap, newList, ownerID, this.__hash);
    };

    return OrderedMap;
  }(Map));

  OrderedMap.isOrderedMap = isOrderedMap;

  OrderedMap.prototype[IS_ORDERED_SYMBOL] = true;
  OrderedMap.prototype[DELETE] = OrderedMap.prototype.remove;

  function makeOrderedMap(map, list, ownerID, hash) {
    var omap = Object.create(OrderedMap.prototype);
    omap.size = map ? map.size : 0;
    omap._map = map;
    omap._list = list;
    omap.__ownerID = ownerID;
    omap.__hash = hash;
    omap.__altered = false;
    return omap;
  }

  var EMPTY_ORDERED_MAP;
  function emptyOrderedMap() {
    return (
      EMPTY_ORDERED_MAP ||
      (EMPTY_ORDERED_MAP = makeOrderedMap(emptyMap(), emptyList()))
    );
  }

  function updateOrderedMap(omap, k, v) {
    var map = omap._map;
    var list = omap._list;
    var i = map.get(k);
    var has = i !== undefined;
    var newMap;
    var newList;
    if (v === NOT_SET) {
      // removed
      if (!has) {
        return omap;
      }
      if (list.size >= SIZE && list.size >= map.size * 2) {
        newList = list.filter(function (entry, idx) { return entry !== undefined && i !== idx; });
        newMap = newList
          .toKeyedSeq()
          .map(function (entry) { return entry[0]; })
          .flip()
          .toMap();
        if (omap.__ownerID) {
          newMap.__ownerID = newList.__ownerID = omap.__ownerID;
        }
      } else {
        newMap = map.remove(k);
        newList = i === list.size - 1 ? list.pop() : list.set(i, undefined);
      }
    } else if (has) {
      if (v === list.get(i)[1]) {
        return omap;
      }
      newMap = map;
      newList = list.set(i, [k, v]);
    } else {
      newMap = map.set(k, list.size);
      newList = list.set(list.size, [k, v]);
    }
    if (omap.__ownerID) {
      omap.size = newMap.size;
      omap._map = newMap;
      omap._list = newList;
      omap.__hash = undefined;
      omap.__altered = true;
      return omap;
    }
    return makeOrderedMap(newMap, newList);
  }

  var IS_STACK_SYMBOL = '@@__IMMUTABLE_STACK__@@';

  function isStack(maybeStack) {
    return Boolean(maybeStack && maybeStack[IS_STACK_SYMBOL]);
  }

  var Stack = /*@__PURE__*/(function (IndexedCollection) {
    function Stack(value) {
      return value === null || value === undefined
        ? emptyStack()
        : isStack(value)
        ? value
        : emptyStack().pushAll(value);
    }

    if ( IndexedCollection ) Stack.__proto__ = IndexedCollection;
    Stack.prototype = Object.create( IndexedCollection && IndexedCollection.prototype );
    Stack.prototype.constructor = Stack;

    Stack.of = function of (/*...values*/) {
      return this(arguments);
    };

    Stack.prototype.toString = function toString () {
      return this.__toString('Stack [', ']');
    };

    // @pragma Access

    Stack.prototype.get = function get (index, notSetValue) {
      var head = this._head;
      index = wrapIndex(this, index);
      while (head && index--) {
        head = head.next;
      }
      return head ? head.value : notSetValue;
    };

    Stack.prototype.peek = function peek () {
      return this._head && this._head.value;
    };

    // @pragma Modification

    Stack.prototype.push = function push (/*...values*/) {
      var arguments$1 = arguments;

      if (arguments.length === 0) {
        return this;
      }
      var newSize = this.size + arguments.length;
      var head = this._head;
      for (var ii = arguments.length - 1; ii >= 0; ii--) {
        head = {
          value: arguments$1[ii],
          next: head,
        };
      }
      if (this.__ownerID) {
        this.size = newSize;
        this._head = head;
        this.__hash = undefined;
        this.__altered = true;
        return this;
      }
      return makeStack(newSize, head);
    };

    Stack.prototype.pushAll = function pushAll (iter) {
      iter = IndexedCollection(iter);
      if (iter.size === 0) {
        return this;
      }
      if (this.size === 0 && isStack(iter)) {
        return iter;
      }
      assertNotInfinite(iter.size);
      var newSize = this.size;
      var head = this._head;
      iter.__iterate(function (value) {
        newSize++;
        head = {
          value: value,
          next: head,
        };
      }, /* reverse */ true);
      if (this.__ownerID) {
        this.size = newSize;
        this._head = head;
        this.__hash = undefined;
        this.__altered = true;
        return this;
      }
      return makeStack(newSize, head);
    };

    Stack.prototype.pop = function pop () {
      return this.slice(1);
    };

    Stack.prototype.clear = function clear () {
      if (this.size === 0) {
        return this;
      }
      if (this.__ownerID) {
        this.size = 0;
        this._head = undefined;
        this.__hash = undefined;
        this.__altered = true;
        return this;
      }
      return emptyStack();
    };

    Stack.prototype.slice = function slice (begin, end) {
      if (wholeSlice(begin, end, this.size)) {
        return this;
      }
      var resolvedBegin = resolveBegin(begin, this.size);
      var resolvedEnd = resolveEnd(end, this.size);
      if (resolvedEnd !== this.size) {
        // super.slice(begin, end);
        return IndexedCollection.prototype.slice.call(this, begin, end);
      }
      var newSize = this.size - resolvedBegin;
      var head = this._head;
      while (resolvedBegin--) {
        head = head.next;
      }
      if (this.__ownerID) {
        this.size = newSize;
        this._head = head;
        this.__hash = undefined;
        this.__altered = true;
        return this;
      }
      return makeStack(newSize, head);
    };

    // @pragma Mutability

    Stack.prototype.__ensureOwner = function __ensureOwner (ownerID) {
      if (ownerID === this.__ownerID) {
        return this;
      }
      if (!ownerID) {
        if (this.size === 0) {
          return emptyStack();
        }
        this.__ownerID = ownerID;
        this.__altered = false;
        return this;
      }
      return makeStack(this.size, this._head, ownerID, this.__hash);
    };

    // @pragma Iteration

    Stack.prototype.__iterate = function __iterate (fn, reverse) {
      var this$1$1 = this;

      if (reverse) {
        return new ArraySeq(this.toArray()).__iterate(
          function (v, k) { return fn(v, k, this$1$1); },
          reverse
        );
      }
      var iterations = 0;
      var node = this._head;
      while (node) {
        if (fn(node.value, iterations++, this) === false) {
          break;
        }
        node = node.next;
      }
      return iterations;
    };

    Stack.prototype.__iterator = function __iterator (type, reverse) {
      if (reverse) {
        return new ArraySeq(this.toArray()).__iterator(type, reverse);
      }
      var iterations = 0;
      var node = this._head;
      return new Iterator(function () {
        if (node) {
          var value = node.value;
          node = node.next;
          return iteratorValue(type, iterations++, value);
        }
        return iteratorDone();
      });
    };

    return Stack;
  }(IndexedCollection));

  Stack.isStack = isStack;

  var StackPrototype = Stack.prototype;
  StackPrototype[IS_STACK_SYMBOL] = true;
  StackPrototype.shift = StackPrototype.pop;
  StackPrototype.unshift = StackPrototype.push;
  StackPrototype.unshiftAll = StackPrototype.pushAll;
  StackPrototype.withMutations = withMutations;
  StackPrototype.wasAltered = wasAltered;
  StackPrototype.asImmutable = asImmutable;
  StackPrototype['@@transducer/init'] = StackPrototype.asMutable = asMutable;
  StackPrototype['@@transducer/step'] = function (result, arr) {
    return result.unshift(arr);
  };
  StackPrototype['@@transducer/result'] = function (obj) {
    return obj.asImmutable();
  };

  function makeStack(size, head, ownerID, hash) {
    var map = Object.create(StackPrototype);
    map.size = size;
    map._head = head;
    map.__ownerID = ownerID;
    map.__hash = hash;
    map.__altered = false;
    return map;
  }

  var EMPTY_STACK;
  function emptyStack() {
    return EMPTY_STACK || (EMPTY_STACK = makeStack(0));
  }

  var IS_SET_SYMBOL = '@@__IMMUTABLE_SET__@@';

  function isSet(maybeSet) {
    return Boolean(maybeSet && maybeSet[IS_SET_SYMBOL]);
  }

  function isOrderedSet(maybeOrderedSet) {
    return isSet(maybeOrderedSet) && isOrdered(maybeOrderedSet);
  }

  function deepEqual(a, b) {
    if (a === b) {
      return true;
    }

    if (
      !isCollection(b) ||
      (a.size !== undefined && b.size !== undefined && a.size !== b.size) ||
      (a.__hash !== undefined &&
        b.__hash !== undefined &&
        a.__hash !== b.__hash) ||
      isKeyed(a) !== isKeyed(b) ||
      isIndexed(a) !== isIndexed(b) ||
      isOrdered(a) !== isOrdered(b)
    ) {
      return false;
    }

    if (a.size === 0 && b.size === 0) {
      return true;
    }

    var notAssociative = !isAssociative(a);

    if (isOrdered(a)) {
      var entries = a.entries();
      return (
        b.every(function (v, k) {
          var entry = entries.next().value;
          return entry && is(entry[1], v) && (notAssociative || is(entry[0], k));
        }) && entries.next().done
      );
    }

    var flipped = false;

    if (a.size === undefined) {
      if (b.size === undefined) {
        if (typeof a.cacheResult === 'function') {
          a.cacheResult();
        }
      } else {
        flipped = true;
        var _ = a;
        a = b;
        b = _;
      }
    }

    var allEqual = true;
    var bSize = b.__iterate(function (v, k) {
      if (
        notAssociative
          ? !a.has(v)
          : flipped
          ? !is(v, a.get(k, NOT_SET))
          : !is(a.get(k, NOT_SET), v)
      ) {
        allEqual = false;
        return false;
      }
    });

    return allEqual && a.size === bSize;
  }

  function mixin(ctor, methods) {
    var keyCopier = function (key) {
      ctor.prototype[key] = methods[key];
    };
    Object.keys(methods).forEach(keyCopier);
    Object.getOwnPropertySymbols &&
      Object.getOwnPropertySymbols(methods).forEach(keyCopier);
    return ctor;
  }

  function toJS(value) {
    if (!value || typeof value !== 'object') {
      return value;
    }
    if (!isCollection(value)) {
      if (!isDataStructure(value)) {
        return value;
      }
      value = Seq(value);
    }
    if (isKeyed(value)) {
      var result$1 = {};
      value.__iterate(function (v, k) {
        result$1[k] = toJS(v);
      });
      return result$1;
    }
    var result = [];
    value.__iterate(function (v) {
      result.push(toJS(v));
    });
    return result;
  }

  var Set = /*@__PURE__*/(function (SetCollection) {
    function Set(value) {
      return value === null || value === undefined
        ? emptySet()
        : isSet(value) && !isOrdered(value)
        ? value
        : emptySet().withMutations(function (set) {
            var iter = SetCollection(value);
            assertNotInfinite(iter.size);
            iter.forEach(function (v) { return set.add(v); });
          });
    }

    if ( SetCollection ) Set.__proto__ = SetCollection;
    Set.prototype = Object.create( SetCollection && SetCollection.prototype );
    Set.prototype.constructor = Set;

    Set.of = function of (/*...values*/) {
      return this(arguments);
    };

    Set.fromKeys = function fromKeys (value) {
      return this(KeyedCollection(value).keySeq());
    };

    Set.intersect = function intersect (sets) {
      sets = Collection(sets).toArray();
      return sets.length
        ? SetPrototype.intersect.apply(Set(sets.pop()), sets)
        : emptySet();
    };

    Set.union = function union (sets) {
      sets = Collection(sets).toArray();
      return sets.length
        ? SetPrototype.union.apply(Set(sets.pop()), sets)
        : emptySet();
    };

    Set.prototype.toString = function toString () {
      return this.__toString('Set {', '}');
    };

    // @pragma Access

    Set.prototype.has = function has (value) {
      return this._map.has(value);
    };

    // @pragma Modification

    Set.prototype.add = function add (value) {
      return updateSet(this, this._map.set(value, value));
    };

    Set.prototype.remove = function remove (value) {
      return updateSet(this, this._map.remove(value));
    };

    Set.prototype.clear = function clear () {
      return updateSet(this, this._map.clear());
    };

    // @pragma Composition

    Set.prototype.map = function map (mapper, context) {
      var this$1$1 = this;

      // keep track if the set is altered by the map function
      var didChanges = false;

      var newMap = updateSet(
        this,
        this._map.mapEntries(function (ref) {
          var v = ref[1];

          var mapped = mapper.call(context, v, v, this$1$1);

          if (mapped !== v) {
            didChanges = true;
          }

          return [mapped, mapped];
        }, context)
      );

      return didChanges ? newMap : this;
    };

    Set.prototype.union = function union () {
      var iters = [], len = arguments.length;
      while ( len-- ) iters[ len ] = arguments[ len ];

      iters = iters.filter(function (x) { return x.size !== 0; });
      if (iters.length === 0) {
        return this;
      }
      if (this.size === 0 && !this.__ownerID && iters.length === 1) {
        return this.constructor(iters[0]);
      }
      return this.withMutations(function (set) {
        for (var ii = 0; ii < iters.length; ii++) {
          SetCollection(iters[ii]).forEach(function (value) { return set.add(value); });
        }
      });
    };

    Set.prototype.intersect = function intersect () {
      var iters = [], len = arguments.length;
      while ( len-- ) iters[ len ] = arguments[ len ];

      if (iters.length === 0) {
        return this;
      }
      iters = iters.map(function (iter) { return SetCollection(iter); });
      var toRemove = [];
      this.forEach(function (value) {
        if (!iters.every(function (iter) { return iter.includes(value); })) {
          toRemove.push(value);
        }
      });
      return this.withMutations(function (set) {
        toRemove.forEach(function (value) {
          set.remove(value);
        });
      });
    };

    Set.prototype.subtract = function subtract () {
      var iters = [], len = arguments.length;
      while ( len-- ) iters[ len ] = arguments[ len ];

      if (iters.length === 0) {
        return this;
      }
      iters = iters.map(function (iter) { return SetCollection(iter); });
      var toRemove = [];
      this.forEach(function (value) {
        if (iters.some(function (iter) { return iter.includes(value); })) {
          toRemove.push(value);
        }
      });
      return this.withMutations(function (set) {
        toRemove.forEach(function (value) {
          set.remove(value);
        });
      });
    };

    Set.prototype.sort = function sort (comparator) {
      // Late binding
      return OrderedSet(sortFactory(this, comparator));
    };

    Set.prototype.sortBy = function sortBy (mapper, comparator) {
      // Late binding
      return OrderedSet(sortFactory(this, comparator, mapper));
    };

    Set.prototype.wasAltered = function wasAltered () {
      return this._map.wasAltered();
    };

    Set.prototype.__iterate = function __iterate (fn, reverse) {
      var this$1$1 = this;

      return this._map.__iterate(function (k) { return fn(k, k, this$1$1); }, reverse);
    };

    Set.prototype.__iterator = function __iterator (type, reverse) {
      return this._map.__iterator(type, reverse);
    };

    Set.prototype.__ensureOwner = function __ensureOwner (ownerID) {
      if (ownerID === this.__ownerID) {
        return this;
      }
      var newMap = this._map.__ensureOwner(ownerID);
      if (!ownerID) {
        if (this.size === 0) {
          return this.__empty();
        }
        this.__ownerID = ownerID;
        this._map = newMap;
        return this;
      }
      return this.__make(newMap, ownerID);
    };

    return Set;
  }(SetCollection));

  Set.isSet = isSet;

  var SetPrototype = Set.prototype;
  SetPrototype[IS_SET_SYMBOL] = true;
  SetPrototype[DELETE] = SetPrototype.remove;
  SetPrototype.merge = SetPrototype.concat = SetPrototype.union;
  SetPrototype.withMutations = withMutations;
  SetPrototype.asImmutable = asImmutable;
  SetPrototype['@@transducer/init'] = SetPrototype.asMutable = asMutable;
  SetPrototype['@@transducer/step'] = function (result, arr) {
    return result.add(arr);
  };
  SetPrototype['@@transducer/result'] = function (obj) {
    return obj.asImmutable();
  };

  SetPrototype.__empty = emptySet;
  SetPrototype.__make = makeSet;

  function updateSet(set, newMap) {
    if (set.__ownerID) {
      set.size = newMap.size;
      set._map = newMap;
      return set;
    }
    return newMap === set._map
      ? set
      : newMap.size === 0
      ? set.__empty()
      : set.__make(newMap);
  }

  function makeSet(map, ownerID) {
    var set = Object.create(SetPrototype);
    set.size = map ? map.size : 0;
    set._map = map;
    set.__ownerID = ownerID;
    return set;
  }

  var EMPTY_SET;
  function emptySet() {
    return EMPTY_SET || (EMPTY_SET = makeSet(emptyMap()));
  }

  /**
   * Returns a lazy seq of nums from start (inclusive) to end
   * (exclusive), by step, where start defaults to 0, step to 1, and end to
   * infinity. When start is equal to end, returns empty list.
   */
  var Range = /*@__PURE__*/(function (IndexedSeq) {
    function Range(start, end, step) {
      if (!(this instanceof Range)) {
        return new Range(start, end, step);
      }
      invariant(step !== 0, 'Cannot step a Range by 0');
      start = start || 0;
      if (end === undefined) {
        end = Infinity;
      }
      step = step === undefined ? 1 : Math.abs(step);
      if (end < start) {
        step = -step;
      }
      this._start = start;
      this._end = end;
      this._step = step;
      this.size = Math.max(0, Math.ceil((end - start) / step - 1) + 1);
      if (this.size === 0) {
        if (EMPTY_RANGE) {
          return EMPTY_RANGE;
        }
        EMPTY_RANGE = this;
      }
    }

    if ( IndexedSeq ) Range.__proto__ = IndexedSeq;
    Range.prototype = Object.create( IndexedSeq && IndexedSeq.prototype );
    Range.prototype.constructor = Range;

    Range.prototype.toString = function toString () {
      if (this.size === 0) {
        return 'Range []';
      }
      return (
        'Range [ ' +
        this._start +
        '...' +
        this._end +
        (this._step !== 1 ? ' by ' + this._step : '') +
        ' ]'
      );
    };

    Range.prototype.get = function get (index, notSetValue) {
      return this.has(index)
        ? this._start + wrapIndex(this, index) * this._step
        : notSetValue;
    };

    Range.prototype.includes = function includes (searchValue) {
      var possibleIndex = (searchValue - this._start) / this._step;
      return (
        possibleIndex >= 0 &&
        possibleIndex < this.size &&
        possibleIndex === Math.floor(possibleIndex)
      );
    };

    Range.prototype.slice = function slice (begin, end) {
      if (wholeSlice(begin, end, this.size)) {
        return this;
      }
      begin = resolveBegin(begin, this.size);
      end = resolveEnd(end, this.size);
      if (end <= begin) {
        return new Range(0, 0);
      }
      return new Range(
        this.get(begin, this._end),
        this.get(end, this._end),
        this._step
      );
    };

    Range.prototype.indexOf = function indexOf (searchValue) {
      var offsetValue = searchValue - this._start;
      if (offsetValue % this._step === 0) {
        var index = offsetValue / this._step;
        if (index >= 0 && index < this.size) {
          return index;
        }
      }
      return -1;
    };

    Range.prototype.lastIndexOf = function lastIndexOf (searchValue) {
      return this.indexOf(searchValue);
    };

    Range.prototype.__iterate = function __iterate (fn, reverse) {
      var size = this.size;
      var step = this._step;
      var value = reverse ? this._start + (size - 1) * step : this._start;
      var i = 0;
      while (i !== size) {
        if (fn(value, reverse ? size - ++i : i++, this) === false) {
          break;
        }
        value += reverse ? -step : step;
      }
      return i;
    };

    Range.prototype.__iterator = function __iterator (type, reverse) {
      var size = this.size;
      var step = this._step;
      var value = reverse ? this._start + (size - 1) * step : this._start;
      var i = 0;
      return new Iterator(function () {
        if (i === size) {
          return iteratorDone();
        }
        var v = value;
        value += reverse ? -step : step;
        return iteratorValue(type, reverse ? size - ++i : i++, v);
      });
    };

    Range.prototype.equals = function equals (other) {
      return other instanceof Range
        ? this._start === other._start &&
            this._end === other._end &&
            this._step === other._step
        : deepEqual(this, other);
    };

    return Range;
  }(IndexedSeq));

  var EMPTY_RANGE;

  function getIn$1(collection, searchKeyPath, notSetValue) {
    var keyPath = coerceKeyPath(searchKeyPath);
    var i = 0;
    while (i !== keyPath.length) {
      collection = get(collection, keyPath[i++], NOT_SET);
      if (collection === NOT_SET) {
        return notSetValue;
      }
    }
    return collection;
  }

  function getIn(searchKeyPath, notSetValue) {
    return getIn$1(this, searchKeyPath, notSetValue);
  }

  function hasIn$1(collection, keyPath) {
    return getIn$1(collection, keyPath, NOT_SET) !== NOT_SET;
  }

  function hasIn(searchKeyPath) {
    return hasIn$1(this, searchKeyPath);
  }

  function toObject() {
    assertNotInfinite(this.size);
    var object = {};
    this.__iterate(function (v, k) {
      object[k] = v;
    });
    return object;
  }

  // Note: all of these methods are deprecated.
  Collection.isIterable = isCollection;
  Collection.isKeyed = isKeyed;
  Collection.isIndexed = isIndexed;
  Collection.isAssociative = isAssociative;
  Collection.isOrdered = isOrdered;

  Collection.Iterator = Iterator;

  mixin(Collection, {
    // ### Conversion to other types

    toArray: function toArray() {
      assertNotInfinite(this.size);
      var array = new Array(this.size || 0);
      var useTuples = isKeyed(this);
      var i = 0;
      this.__iterate(function (v, k) {
        // Keyed collections produce an array of tuples.
        array[i++] = useTuples ? [k, v] : v;
      });
      return array;
    },

    toIndexedSeq: function toIndexedSeq() {
      return new ToIndexedSequence(this);
    },

    toJS: function toJS$1() {
      return toJS(this);
    },

    toKeyedSeq: function toKeyedSeq() {
      return new ToKeyedSequence(this, true);
    },

    toMap: function toMap() {
      // Use Late Binding here to solve the circular dependency.
      return Map(this.toKeyedSeq());
    },

    toObject: toObject,

    toOrderedMap: function toOrderedMap() {
      // Use Late Binding here to solve the circular dependency.
      return OrderedMap(this.toKeyedSeq());
    },

    toOrderedSet: function toOrderedSet() {
      // Use Late Binding here to solve the circular dependency.
      return OrderedSet(isKeyed(this) ? this.valueSeq() : this);
    },

    toSet: function toSet() {
      // Use Late Binding here to solve the circular dependency.
      return Set(isKeyed(this) ? this.valueSeq() : this);
    },

    toSetSeq: function toSetSeq() {
      return new ToSetSequence(this);
    },

    toSeq: function toSeq() {
      return isIndexed(this)
        ? this.toIndexedSeq()
        : isKeyed(this)
        ? this.toKeyedSeq()
        : this.toSetSeq();
    },

    toStack: function toStack() {
      // Use Late Binding here to solve the circular dependency.
      return Stack(isKeyed(this) ? this.valueSeq() : this);
    },

    toList: function toList() {
      // Use Late Binding here to solve the circular dependency.
      return List(isKeyed(this) ? this.valueSeq() : this);
    },

    // ### Common JavaScript methods and properties

    toString: function toString() {
      return '[Collection]';
    },

    __toString: function __toString(head, tail) {
      if (this.size === 0) {
        return head + tail;
      }
      return (
        head +
        ' ' +
        this.toSeq().map(this.__toStringMapper).join(', ') +
        ' ' +
        tail
      );
    },

    // ### ES6 Collection methods (ES6 Array and Map)

    concat: function concat() {
      var values = [], len = arguments.length;
      while ( len-- ) values[ len ] = arguments[ len ];

      return reify(this, concatFactory(this, values));
    },

    includes: function includes(searchValue) {
      return this.some(function (value) { return is(value, searchValue); });
    },

    entries: function entries() {
      return this.__iterator(ITERATE_ENTRIES);
    },

    every: function every(predicate, context) {
      assertNotInfinite(this.size);
      var returnValue = true;
      this.__iterate(function (v, k, c) {
        if (!predicate.call(context, v, k, c)) {
          returnValue = false;
          return false;
        }
      });
      return returnValue;
    },

    filter: function filter(predicate, context) {
      return reify(this, filterFactory(this, predicate, context, true));
    },

    find: function find(predicate, context, notSetValue) {
      var entry = this.findEntry(predicate, context);
      return entry ? entry[1] : notSetValue;
    },

    forEach: function forEach(sideEffect, context) {
      assertNotInfinite(this.size);
      return this.__iterate(context ? sideEffect.bind(context) : sideEffect);
    },

    join: function join(separator) {
      assertNotInfinite(this.size);
      separator = separator !== undefined ? '' + separator : ',';
      var joined = '';
      var isFirst = true;
      this.__iterate(function (v) {
        isFirst ? (isFirst = false) : (joined += separator);
        joined += v !== null && v !== undefined ? v.toString() : '';
      });
      return joined;
    },

    keys: function keys() {
      return this.__iterator(ITERATE_KEYS);
    },

    map: function map(mapper, context) {
      return reify(this, mapFactory(this, mapper, context));
    },

    reduce: function reduce$1(reducer, initialReduction, context) {
      return reduce(
        this,
        reducer,
        initialReduction,
        context,
        arguments.length < 2,
        false
      );
    },

    reduceRight: function reduceRight(reducer, initialReduction, context) {
      return reduce(
        this,
        reducer,
        initialReduction,
        context,
        arguments.length < 2,
        true
      );
    },

    reverse: function reverse() {
      return reify(this, reverseFactory(this, true));
    },

    slice: function slice(begin, end) {
      return reify(this, sliceFactory(this, begin, end, true));
    },

    some: function some(predicate, context) {
      return !this.every(not(predicate), context);
    },

    sort: function sort(comparator) {
      return reify(this, sortFactory(this, comparator));
    },

    values: function values() {
      return this.__iterator(ITERATE_VALUES);
    },

    // ### More sequential methods

    butLast: function butLast() {
      return this.slice(0, -1);
    },

    isEmpty: function isEmpty() {
      return this.size !== undefined ? this.size === 0 : !this.some(function () { return true; });
    },

    count: function count(predicate, context) {
      return ensureSize(
        predicate ? this.toSeq().filter(predicate, context) : this
      );
    },

    countBy: function countBy(grouper, context) {
      return countByFactory(this, grouper, context);
    },

    equals: function equals(other) {
      return deepEqual(this, other);
    },

    entrySeq: function entrySeq() {
      var collection = this;
      if (collection._cache) {
        // We cache as an entries array, so we can just return the cache!
        return new ArraySeq(collection._cache);
      }
      var entriesSequence = collection.toSeq().map(entryMapper).toIndexedSeq();
      entriesSequence.fromEntrySeq = function () { return collection.toSeq(); };
      return entriesSequence;
    },

    filterNot: function filterNot(predicate, context) {
      return this.filter(not(predicate), context);
    },

    findEntry: function findEntry(predicate, context, notSetValue) {
      var found = notSetValue;
      this.__iterate(function (v, k, c) {
        if (predicate.call(context, v, k, c)) {
          found = [k, v];
          return false;
        }
      });
      return found;
    },

    findKey: function findKey(predicate, context) {
      var entry = this.findEntry(predicate, context);
      return entry && entry[0];
    },

    findLast: function findLast(predicate, context, notSetValue) {
      return this.toKeyedSeq().reverse().find(predicate, context, notSetValue);
    },

    findLastEntry: function findLastEntry(predicate, context, notSetValue) {
      return this.toKeyedSeq()
        .reverse()
        .findEntry(predicate, context, notSetValue);
    },

    findLastKey: function findLastKey(predicate, context) {
      return this.toKeyedSeq().reverse().findKey(predicate, context);
    },

    first: function first(notSetValue) {
      return this.find(returnTrue, null, notSetValue);
    },

    flatMap: function flatMap(mapper, context) {
      return reify(this, flatMapFactory(this, mapper, context));
    },

    flatten: function flatten(depth) {
      return reify(this, flattenFactory(this, depth, true));
    },

    fromEntrySeq: function fromEntrySeq() {
      return new FromEntriesSequence(this);
    },

    get: function get(searchKey, notSetValue) {
      return this.find(function (_, key) { return is(key, searchKey); }, undefined, notSetValue);
    },

    getIn: getIn,

    groupBy: function groupBy(grouper, context) {
      return groupByFactory(this, grouper, context);
    },

    has: function has(searchKey) {
      return this.get(searchKey, NOT_SET) !== NOT_SET;
    },

    hasIn: hasIn,

    isSubset: function isSubset(iter) {
      iter = typeof iter.includes === 'function' ? iter : Collection(iter);
      return this.every(function (value) { return iter.includes(value); });
    },

    isSuperset: function isSuperset(iter) {
      iter = typeof iter.isSubset === 'function' ? iter : Collection(iter);
      return iter.isSubset(this);
    },

    keyOf: function keyOf(searchValue) {
      return this.findKey(function (value) { return is(value, searchValue); });
    },

    keySeq: function keySeq() {
      return this.toSeq().map(keyMapper).toIndexedSeq();
    },

    last: function last(notSetValue) {
      return this.toSeq().reverse().first(notSetValue);
    },

    lastKeyOf: function lastKeyOf(searchValue) {
      return this.toKeyedSeq().reverse().keyOf(searchValue);
    },

    max: function max(comparator) {
      return maxFactory(this, comparator);
    },

    maxBy: function maxBy(mapper, comparator) {
      return maxFactory(this, comparator, mapper);
    },

    min: function min(comparator) {
      return maxFactory(
        this,
        comparator ? neg(comparator) : defaultNegComparator
      );
    },

    minBy: function minBy(mapper, comparator) {
      return maxFactory(
        this,
        comparator ? neg(comparator) : defaultNegComparator,
        mapper
      );
    },

    rest: function rest() {
      return this.slice(1);
    },

    skip: function skip(amount) {
      return amount === 0 ? this : this.slice(Math.max(0, amount));
    },

    skipLast: function skipLast(amount) {
      return amount === 0 ? this : this.slice(0, -Math.max(0, amount));
    },

    skipWhile: function skipWhile(predicate, context) {
      return reify(this, skipWhileFactory(this, predicate, context, true));
    },

    skipUntil: function skipUntil(predicate, context) {
      return this.skipWhile(not(predicate), context);
    },

    sortBy: function sortBy(mapper, comparator) {
      return reify(this, sortFactory(this, comparator, mapper));
    },

    take: function take(amount) {
      return this.slice(0, Math.max(0, amount));
    },

    takeLast: function takeLast(amount) {
      return this.slice(-Math.max(0, amount));
    },

    takeWhile: function takeWhile(predicate, context) {
      return reify(this, takeWhileFactory(this, predicate, context));
    },

    takeUntil: function takeUntil(predicate, context) {
      return this.takeWhile(not(predicate), context);
    },

    update: function update(fn) {
      return fn(this);
    },

    valueSeq: function valueSeq() {
      return this.toIndexedSeq();
    },

    // ### Hashable Object

    hashCode: function hashCode() {
      return this.__hash || (this.__hash = hashCollection(this));
    },

    // ### Internal

    // abstract __iterate(fn, reverse)

    // abstract __iterator(type, reverse)
  });

  var CollectionPrototype = Collection.prototype;
  CollectionPrototype[IS_COLLECTION_SYMBOL] = true;
  CollectionPrototype[ITERATOR_SYMBOL] = CollectionPrototype.values;
  CollectionPrototype.toJSON = CollectionPrototype.toArray;
  CollectionPrototype.__toStringMapper = quoteString;
  CollectionPrototype.inspect = CollectionPrototype.toSource = function () {
    return this.toString();
  };
  CollectionPrototype.chain = CollectionPrototype.flatMap;
  CollectionPrototype.contains = CollectionPrototype.includes;

  mixin(KeyedCollection, {
    // ### More sequential methods

    flip: function flip() {
      return reify(this, flipFactory(this));
    },

    mapEntries: function mapEntries(mapper, context) {
      var this$1$1 = this;

      var iterations = 0;
      return reify(
        this,
        this.toSeq()
          .map(function (v, k) { return mapper.call(context, [k, v], iterations++, this$1$1); })
          .fromEntrySeq()
      );
    },

    mapKeys: function mapKeys(mapper, context) {
      var this$1$1 = this;

      return reify(
        this,
        this.toSeq()
          .flip()
          .map(function (k, v) { return mapper.call(context, k, v, this$1$1); })
          .flip()
      );
    },
  });

  var KeyedCollectionPrototype = KeyedCollection.prototype;
  KeyedCollectionPrototype[IS_KEYED_SYMBOL] = true;
  KeyedCollectionPrototype[ITERATOR_SYMBOL] = CollectionPrototype.entries;
  KeyedCollectionPrototype.toJSON = toObject;
  KeyedCollectionPrototype.__toStringMapper = function (v, k) { return quoteString(k) + ': ' + quoteString(v); };

  mixin(IndexedCollection, {
    // ### Conversion to other types

    toKeyedSeq: function toKeyedSeq() {
      return new ToKeyedSequence(this, false);
    },

    // ### ES6 Collection methods (ES6 Array and Map)

    filter: function filter(predicate, context) {
      return reify(this, filterFactory(this, predicate, context, false));
    },

    findIndex: function findIndex(predicate, context) {
      var entry = this.findEntry(predicate, context);
      return entry ? entry[0] : -1;
    },

    indexOf: function indexOf(searchValue) {
      var key = this.keyOf(searchValue);
      return key === undefined ? -1 : key;
    },

    lastIndexOf: function lastIndexOf(searchValue) {
      var key = this.lastKeyOf(searchValue);
      return key === undefined ? -1 : key;
    },

    reverse: function reverse() {
      return reify(this, reverseFactory(this, false));
    },

    slice: function slice(begin, end) {
      return reify(this, sliceFactory(this, begin, end, false));
    },

    splice: function splice(index, removeNum /*, ...values*/) {
      var numArgs = arguments.length;
      removeNum = Math.max(removeNum || 0, 0);
      if (numArgs === 0 || (numArgs === 2 && !removeNum)) {
        return this;
      }
      // If index is negative, it should resolve relative to the size of the
      // collection. However size may be expensive to compute if not cached, so
      // only call count() if the number is in fact negative.
      index = resolveBegin(index, index < 0 ? this.count() : this.size);
      var spliced = this.slice(0, index);
      return reify(
        this,
        numArgs === 1
          ? spliced
          : spliced.concat(arrCopy(arguments, 2), this.slice(index + removeNum))
      );
    },

    // ### More collection methods

    findLastIndex: function findLastIndex(predicate, context) {
      var entry = this.findLastEntry(predicate, context);
      return entry ? entry[0] : -1;
    },

    first: function first(notSetValue) {
      return this.get(0, notSetValue);
    },

    flatten: function flatten(depth) {
      return reify(this, flattenFactory(this, depth, false));
    },

    get: function get(index, notSetValue) {
      index = wrapIndex(this, index);
      return index < 0 ||
        this.size === Infinity ||
        (this.size !== undefined && index > this.size)
        ? notSetValue
        : this.find(function (_, key) { return key === index; }, undefined, notSetValue);
    },

    has: function has(index) {
      index = wrapIndex(this, index);
      return (
        index >= 0 &&
        (this.size !== undefined
          ? this.size === Infinity || index < this.size
          : this.indexOf(index) !== -1)
      );
    },

    interpose: function interpose(separator) {
      return reify(this, interposeFactory(this, separator));
    },

    interleave: function interleave(/*...collections*/) {
      var collections = [this].concat(arrCopy(arguments));
      var zipped = zipWithFactory(this.toSeq(), IndexedSeq.of, collections);
      var interleaved = zipped.flatten(true);
      if (zipped.size) {
        interleaved.size = zipped.size * collections.length;
      }
      return reify(this, interleaved);
    },

    keySeq: function keySeq() {
      return Range(0, this.size);
    },

    last: function last(notSetValue) {
      return this.get(-1, notSetValue);
    },

    skipWhile: function skipWhile(predicate, context) {
      return reify(this, skipWhileFactory(this, predicate, context, false));
    },

    zip: function zip(/*, ...collections */) {
      var collections = [this].concat(arrCopy(arguments));
      return reify(this, zipWithFactory(this, defaultZipper, collections));
    },

    zipAll: function zipAll(/*, ...collections */) {
      var collections = [this].concat(arrCopy(arguments));
      return reify(this, zipWithFactory(this, defaultZipper, collections, true));
    },

    zipWith: function zipWith(zipper /*, ...collections */) {
      var collections = arrCopy(arguments);
      collections[0] = this;
      return reify(this, zipWithFactory(this, zipper, collections));
    },
  });

  var IndexedCollectionPrototype = IndexedCollection.prototype;
  IndexedCollectionPrototype[IS_INDEXED_SYMBOL] = true;
  IndexedCollectionPrototype[IS_ORDERED_SYMBOL] = true;

  mixin(SetCollection, {
    // ### ES6 Collection methods (ES6 Array and Map)

    get: function get(value, notSetValue) {
      return this.has(value) ? value : notSetValue;
    },

    includes: function includes(value) {
      return this.has(value);
    },

    // ### More sequential methods

    keySeq: function keySeq() {
      return this.valueSeq();
    },
  });

  var SetCollectionPrototype = SetCollection.prototype;
  SetCollectionPrototype.has = CollectionPrototype.includes;
  SetCollectionPrototype.contains = SetCollectionPrototype.includes;
  SetCollectionPrototype.keys = SetCollectionPrototype.values;

  // Mixin subclasses

  mixin(KeyedSeq, KeyedCollectionPrototype);
  mixin(IndexedSeq, IndexedCollectionPrototype);
  mixin(SetSeq, SetCollectionPrototype);

  // #pragma Helper functions

  function reduce(collection, reducer, reduction, context, useFirst, reverse) {
    assertNotInfinite(collection.size);
    collection.__iterate(function (v, k, c) {
      if (useFirst) {
        useFirst = false;
        reduction = v;
      } else {
        reduction = reducer.call(context, reduction, v, k, c);
      }
    }, reverse);
    return reduction;
  }

  function keyMapper(v, k) {
    return k;
  }

  function entryMapper(v, k) {
    return [k, v];
  }

  function not(predicate) {
    return function () {
      return !predicate.apply(this, arguments);
    };
  }

  function neg(predicate) {
    return function () {
      return -predicate.apply(this, arguments);
    };
  }

  function defaultZipper() {
    return arrCopy(arguments);
  }

  function defaultNegComparator(a, b) {
    return a < b ? 1 : a > b ? -1 : 0;
  }

  function hashCollection(collection) {
    if (collection.size === Infinity) {
      return 0;
    }
    var ordered = isOrdered(collection);
    var keyed = isKeyed(collection);
    var h = ordered ? 1 : 0;
    var size = collection.__iterate(
      keyed
        ? ordered
          ? function (v, k) {
              h = (31 * h + hashMerge(hash(v), hash(k))) | 0;
            }
          : function (v, k) {
              h = (h + hashMerge(hash(v), hash(k))) | 0;
            }
        : ordered
        ? function (v) {
            h = (31 * h + hash(v)) | 0;
          }
        : function (v) {
            h = (h + hash(v)) | 0;
          }
    );
    return murmurHashOfSize(size, h);
  }

  function murmurHashOfSize(size, h) {
    h = imul(h, 0xcc9e2d51);
    h = imul((h << 15) | (h >>> -15), 0x1b873593);
    h = imul((h << 13) | (h >>> -13), 5);
    h = ((h + 0xe6546b64) | 0) ^ size;
    h = imul(h ^ (h >>> 16), 0x85ebca6b);
    h = imul(h ^ (h >>> 13), 0xc2b2ae35);
    h = smi(h ^ (h >>> 16));
    return h;
  }

  function hashMerge(a, b) {
    return (a ^ (b + 0x9e3779b9 + (a << 6) + (a >> 2))) | 0; // int
  }

  var OrderedSet = /*@__PURE__*/(function (Set) {
    function OrderedSet(value) {
      return value === null || value === undefined
        ? emptyOrderedSet()
        : isOrderedSet(value)
        ? value
        : emptyOrderedSet().withMutations(function (set) {
            var iter = SetCollection(value);
            assertNotInfinite(iter.size);
            iter.forEach(function (v) { return set.add(v); });
          });
    }

    if ( Set ) OrderedSet.__proto__ = Set;
    OrderedSet.prototype = Object.create( Set && Set.prototype );
    OrderedSet.prototype.constructor = OrderedSet;

    OrderedSet.of = function of (/*...values*/) {
      return this(arguments);
    };

    OrderedSet.fromKeys = function fromKeys (value) {
      return this(KeyedCollection(value).keySeq());
    };

    OrderedSet.prototype.toString = function toString () {
      return this.__toString('OrderedSet {', '}');
    };

    return OrderedSet;
  }(Set));

  OrderedSet.isOrderedSet = isOrderedSet;

  var OrderedSetPrototype = OrderedSet.prototype;
  OrderedSetPrototype[IS_ORDERED_SYMBOL] = true;
  OrderedSetPrototype.zip = IndexedCollectionPrototype.zip;
  OrderedSetPrototype.zipWith = IndexedCollectionPrototype.zipWith;
  OrderedSetPrototype.zipAll = IndexedCollectionPrototype.zipAll;

  OrderedSetPrototype.__empty = emptyOrderedSet;
  OrderedSetPrototype.__make = makeOrderedSet;

  function makeOrderedSet(map, ownerID) {
    var set = Object.create(OrderedSetPrototype);
    set.size = map ? map.size : 0;
    set._map = map;
    set.__ownerID = ownerID;
    return set;
  }

  var EMPTY_ORDERED_SET;
  function emptyOrderedSet() {
    return (
      EMPTY_ORDERED_SET || (EMPTY_ORDERED_SET = makeOrderedSet(emptyOrderedMap()))
    );
  }

  function throwOnInvalidDefaultValues(defaultValues) {
    if (isRecord(defaultValues)) {
      throw new Error(
        'Can not call `Record` with an immutable Record as default values. Use a plain javascript object instead.'
      );
    }

    if (isImmutable(defaultValues)) {
      throw new Error(
        'Can not call `Record` with an immutable Collection as default values. Use a plain javascript object instead.'
      );
    }

    if (defaultValues === null || typeof defaultValues !== 'object') {
      throw new Error(
        'Can not call `Record` with a non-object as default values. Use a plain javascript object instead.'
      );
    }
  }

  var Record = function Record(defaultValues, name) {
    var hasInitialized;

    throwOnInvalidDefaultValues(defaultValues);

    var RecordType = function Record(values) {
      var this$1$1 = this;

      if (values instanceof RecordType) {
        return values;
      }
      if (!(this instanceof RecordType)) {
        return new RecordType(values);
      }
      if (!hasInitialized) {
        hasInitialized = true;
        var keys = Object.keys(defaultValues);
        var indices = (RecordTypePrototype._indices = {});
        // Deprecated: left to attempt not to break any external code which
        // relies on a ._name property existing on record instances.
        // Use Record.getDescriptiveName() instead
        RecordTypePrototype._name = name;
        RecordTypePrototype._keys = keys;
        RecordTypePrototype._defaultValues = defaultValues;
        for (var i = 0; i < keys.length; i++) {
          var propName = keys[i];
          indices[propName] = i;
          if (RecordTypePrototype[propName]) {
            /* eslint-disable no-console */
            typeof console === 'object' &&
              console.warn &&
              console.warn(
                'Cannot define ' +
                  recordName(this) +
                  ' with property "' +
                  propName +
                  '" since that property name is part of the Record API.'
              );
            /* eslint-enable no-console */
          } else {
            setProp(RecordTypePrototype, propName);
          }
        }
      }
      this.__ownerID = undefined;
      this._values = List().withMutations(function (l) {
        l.setSize(this$1$1._keys.length);
        KeyedCollection(values).forEach(function (v, k) {
          l.set(this$1$1._indices[k], v === this$1$1._defaultValues[k] ? undefined : v);
        });
      });
      return this;
    };

    var RecordTypePrototype = (RecordType.prototype =
      Object.create(RecordPrototype));
    RecordTypePrototype.constructor = RecordType;

    if (name) {
      RecordType.displayName = name;
    }

    return RecordType;
  };

  Record.prototype.toString = function toString () {
    var str = recordName(this) + ' { ';
    var keys = this._keys;
    var k;
    for (var i = 0, l = keys.length; i !== l; i++) {
      k = keys[i];
      str += (i ? ', ' : '') + k + ': ' + quoteString(this.get(k));
    }
    return str + ' }';
  };

  Record.prototype.equals = function equals (other) {
    return (
      this === other || (other && recordSeq(this).equals(recordSeq(other)))
    );
  };

  Record.prototype.hashCode = function hashCode () {
    return recordSeq(this).hashCode();
  };

  // @pragma Access

  Record.prototype.has = function has (k) {
    return this._indices.hasOwnProperty(k);
  };

  Record.prototype.get = function get (k, notSetValue) {
    if (!this.has(k)) {
      return notSetValue;
    }
    var index = this._indices[k];
    var value = this._values.get(index);
    return value === undefined ? this._defaultValues[k] : value;
  };

  // @pragma Modification

  Record.prototype.set = function set (k, v) {
    if (this.has(k)) {
      var newValues = this._values.set(
        this._indices[k],
        v === this._defaultValues[k] ? undefined : v
      );
      if (newValues !== this._values && !this.__ownerID) {
        return makeRecord(this, newValues);
      }
    }
    return this;
  };

  Record.prototype.remove = function remove (k) {
    return this.set(k);
  };

  Record.prototype.clear = function clear () {
    var newValues = this._values.clear().setSize(this._keys.length);

    return this.__ownerID ? this : makeRecord(this, newValues);
  };

  Record.prototype.wasAltered = function wasAltered () {
    return this._values.wasAltered();
  };

  Record.prototype.toSeq = function toSeq () {
    return recordSeq(this);
  };

  Record.prototype.toJS = function toJS$1 () {
    return toJS(this);
  };

  Record.prototype.entries = function entries () {
    return this.__iterator(ITERATE_ENTRIES);
  };

  Record.prototype.__iterator = function __iterator (type, reverse) {
    return recordSeq(this).__iterator(type, reverse);
  };

  Record.prototype.__iterate = function __iterate (fn, reverse) {
    return recordSeq(this).__iterate(fn, reverse);
  };

  Record.prototype.__ensureOwner = function __ensureOwner (ownerID) {
    if (ownerID === this.__ownerID) {
      return this;
    }
    var newValues = this._values.__ensureOwner(ownerID);
    if (!ownerID) {
      this.__ownerID = ownerID;
      this._values = newValues;
      return this;
    }
    return makeRecord(this, newValues, ownerID);
  };

  Record.isRecord = isRecord;
  Record.getDescriptiveName = recordName;
  var RecordPrototype = Record.prototype;
  RecordPrototype[IS_RECORD_SYMBOL] = true;
  RecordPrototype[DELETE] = RecordPrototype.remove;
  RecordPrototype.deleteIn = RecordPrototype.removeIn = deleteIn;
  RecordPrototype.getIn = getIn;
  RecordPrototype.hasIn = CollectionPrototype.hasIn;
  RecordPrototype.merge = merge$1;
  RecordPrototype.mergeWith = mergeWith$1;
  RecordPrototype.mergeIn = mergeIn;
  RecordPrototype.mergeDeep = mergeDeep;
  RecordPrototype.mergeDeepWith = mergeDeepWith;
  RecordPrototype.mergeDeepIn = mergeDeepIn;
  RecordPrototype.setIn = setIn;
  RecordPrototype.update = update;
  RecordPrototype.updateIn = updateIn;
  RecordPrototype.withMutations = withMutations;
  RecordPrototype.asMutable = asMutable;
  RecordPrototype.asImmutable = asImmutable;
  RecordPrototype[ITERATOR_SYMBOL] = RecordPrototype.entries;
  RecordPrototype.toJSON = RecordPrototype.toObject =
    CollectionPrototype.toObject;
  RecordPrototype.inspect = RecordPrototype.toSource = function () {
    return this.toString();
  };

  function makeRecord(likeRecord, values, ownerID) {
    var record = Object.create(Object.getPrototypeOf(likeRecord));
    record._values = values;
    record.__ownerID = ownerID;
    return record;
  }

  function recordName(record) {
    return record.constructor.displayName || record.constructor.name || 'Record';
  }

  function recordSeq(record) {
    return keyedSeqFromValue(record._keys.map(function (k) { return [k, record.get(k)]; }));
  }

  function setProp(prototype, name) {
    try {
      Object.defineProperty(prototype, name, {
        get: function () {
          return this.get(name);
        },
        set: function (value) {
          invariant(this.__ownerID, 'Cannot set on an immutable record.');
          this.set(name, value);
        },
      });
    } catch (error) {
      // Object.defineProperty failed. Probably IE8.
    }
  }

  /**
   * Returns a lazy Seq of `value` repeated `times` times. When `times` is
   * undefined, returns an infinite sequence of `value`.
   */
  var Repeat = /*@__PURE__*/(function (IndexedSeq) {
    function Repeat(value, times) {
      if (!(this instanceof Repeat)) {
        return new Repeat(value, times);
      }
      this._value = value;
      this.size = times === undefined ? Infinity : Math.max(0, times);
      if (this.size === 0) {
        if (EMPTY_REPEAT) {
          return EMPTY_REPEAT;
        }
        EMPTY_REPEAT = this;
      }
    }

    if ( IndexedSeq ) Repeat.__proto__ = IndexedSeq;
    Repeat.prototype = Object.create( IndexedSeq && IndexedSeq.prototype );
    Repeat.prototype.constructor = Repeat;

    Repeat.prototype.toString = function toString () {
      if (this.size === 0) {
        return 'Repeat []';
      }
      return 'Repeat [ ' + this._value + ' ' + this.size + ' times ]';
    };

    Repeat.prototype.get = function get (index, notSetValue) {
      return this.has(index) ? this._value : notSetValue;
    };

    Repeat.prototype.includes = function includes (searchValue) {
      return is(this._value, searchValue);
    };

    Repeat.prototype.slice = function slice (begin, end) {
      var size = this.size;
      return wholeSlice(begin, end, size)
        ? this
        : new Repeat(
            this._value,
            resolveEnd(end, size) - resolveBegin(begin, size)
          );
    };

    Repeat.prototype.reverse = function reverse () {
      return this;
    };

    Repeat.prototype.indexOf = function indexOf (searchValue) {
      if (is(this._value, searchValue)) {
        return 0;
      }
      return -1;
    };

    Repeat.prototype.lastIndexOf = function lastIndexOf (searchValue) {
      if (is(this._value, searchValue)) {
        return this.size;
      }
      return -1;
    };

    Repeat.prototype.__iterate = function __iterate (fn, reverse) {
      var size = this.size;
      var i = 0;
      while (i !== size) {
        if (fn(this._value, reverse ? size - ++i : i++, this) === false) {
          break;
        }
      }
      return i;
    };

    Repeat.prototype.__iterator = function __iterator (type, reverse) {
      var this$1$1 = this;

      var size = this.size;
      var i = 0;
      return new Iterator(function () { return i === size
          ? iteratorDone()
          : iteratorValue(type, reverse ? size - ++i : i++, this$1$1._value); }
      );
    };

    Repeat.prototype.equals = function equals (other) {
      return other instanceof Repeat
        ? is(this._value, other._value)
        : deepEqual(other);
    };

    return Repeat;
  }(IndexedSeq));

  var EMPTY_REPEAT;

  function fromJS(value, converter) {
    return fromJSWith(
      [],
      converter || defaultConverter,
      value,
      '',
      converter && converter.length > 2 ? [] : undefined,
      { '': value }
    );
  }

  function fromJSWith(stack, converter, value, key, keyPath, parentValue) {
    if (
      typeof value !== 'string' &&
      !isImmutable(value) &&
      (isArrayLike(value) || hasIterator(value) || isPlainObject(value))
    ) {
      if (~stack.indexOf(value)) {
        throw new TypeError('Cannot convert circular structure to Immutable');
      }
      stack.push(value);
      keyPath && key !== '' && keyPath.push(key);
      var converted = converter.call(
        parentValue,
        key,
        Seq(value).map(function (v, k) { return fromJSWith(stack, converter, v, k, keyPath, value); }
        ),
        keyPath && keyPath.slice()
      );
      stack.pop();
      keyPath && keyPath.pop();
      return converted;
    }
    return value;
  }

  function defaultConverter(k, v) {
    // Effectively the opposite of "Collection.toSeq()"
    return isIndexed(v) ? v.toList() : isKeyed(v) ? v.toMap() : v.toSet();
  }

  var version = "4.0.0";

  var Immutable = {
    version: version,

    Collection: Collection,
    // Note: Iterable is deprecated
    Iterable: Collection,

    Seq: Seq,
    Map: Map,
    OrderedMap: OrderedMap,
    List: List,
    Stack: Stack,
    Set: Set,
    OrderedSet: OrderedSet,

    Record: Record,
    Range: Range,
    Repeat: Repeat,

    is: is,
    fromJS: fromJS,
    hash: hash,

    isImmutable: isImmutable,
    isCollection: isCollection,
    isKeyed: isKeyed,
    isIndexed: isIndexed,
    isAssociative: isAssociative,
    isOrdered: isOrdered,
    isValueObject: isValueObject,
    isPlainObject: isPlainObject,
    isSeq: isSeq,
    isList: isList,
    isMap: isMap,
    isOrderedMap: isOrderedMap,
    isStack: isStack,
    isSet: isSet,
    isOrderedSet: isOrderedSet,
    isRecord: isRecord,

    get: get,
    getIn: getIn$1,
    has: has,
    hasIn: hasIn$1,
    merge: merge,
    mergeDeep: mergeDeep$1,
    mergeWith: mergeWith,
    mergeDeepWith: mergeDeepWith$1,
    remove: remove,
    removeIn: removeIn,
    set: set,
    setIn: setIn$1,
    update: update$1,
    updateIn: updateIn$1,
  };

  // Note: Iterable is deprecated
  var Iterable = Collection;

  exports.Collection = Collection;
  exports.Iterable = Iterable;
  exports.List = List;
  exports.Map = Map;
  exports.OrderedMap = OrderedMap;
  exports.OrderedSet = OrderedSet;
  exports.Range = Range;
  exports.Record = Record;
  exports.Repeat = Repeat;
  exports.Seq = Seq;
  exports.Set = Set;
  exports.Stack = Stack;
  exports.default = Immutable;
  exports.fromJS = fromJS;
  exports.get = get;
  exports.getIn = getIn$1;
  exports.has = has;
  exports.hasIn = hasIn$1;
  exports.hash = hash;
  exports.is = is;
  exports.isAssociative = isAssociative;
  exports.isCollection = isCollection;
  exports.isImmutable = isImmutable;
  exports.isIndexed = isIndexed;
  exports.isKeyed = isKeyed;
  exports.isList = isList;
  exports.isMap = isMap;
  exports.isOrdered = isOrdered;
  exports.isOrderedMap = isOrderedMap;
  exports.isOrderedSet = isOrderedSet;
  exports.isPlainObject = isPlainObject;
  exports.isRecord = isRecord;
  exports.isSeq = isSeq;
  exports.isSet = isSet;
  exports.isStack = isStack;
  exports.isValueObject = isValueObject;
  exports.merge = merge;
  exports.mergeDeep = mergeDeep$1;
  exports.mergeDeepWith = mergeDeepWith$1;
  exports.mergeWith = mergeWith;
  exports.remove = remove;
  exports.removeIn = removeIn;
  exports.set = set;
  exports.setIn = setIn$1;
  exports.update = update$1;
  exports.updateIn = updateIn$1;
  exports.version = version;

  Object.defineProperty(exports, '__esModule', { value: true });

})));