51 lines
1.4 KiB
JavaScript
Vendored
51 lines
1.4 KiB
JavaScript
Vendored
"use strict";
|
|
|
|
var isObject = require("type/object/is")
|
|
, ensureNaturalNumber = require("type/natural-number/ensure")
|
|
, ensureString = require("type/string/ensure");
|
|
|
|
var generated = Object.create(null), random = Math.random, uniqTryLimit = 100;
|
|
|
|
var getChunk = function () { return random().toString(36).slice(2); };
|
|
|
|
var getString = function (length, charset) {
|
|
var str;
|
|
if (charset) {
|
|
var charsetLength = charset.length;
|
|
str = "";
|
|
for (var i = 0; i < length; ++i) {
|
|
str += charset.charAt(Math.floor(Math.random() * charsetLength));
|
|
}
|
|
return str;
|
|
}
|
|
str = getChunk();
|
|
if (length === null) return str;
|
|
while (str.length < length) str += getChunk();
|
|
return str.slice(0, length);
|
|
};
|
|
|
|
module.exports = function (/* options */) {
|
|
var options = arguments[0];
|
|
if (!isObject(options)) options = {};
|
|
var length = ensureNaturalNumber(options.length, { "default": 10 })
|
|
, isUnique = options.isUnique
|
|
, charset = ensureString(options.charset, { isOptional: true });
|
|
|
|
var str = getString(length, charset);
|
|
if (isUnique) {
|
|
var count = 0;
|
|
while (generated[str]) {
|
|
if (++count === uniqTryLimit) {
|
|
throw new Error(
|
|
"Cannot generate random string.\n" +
|
|
"String.random is not designed to effectively generate many short and " +
|
|
"unique random strings"
|
|
);
|
|
}
|
|
str = getString(length);
|
|
}
|
|
generated[str] = true;
|
|
}
|
|
return str;
|
|
};
|