87 lines
2.7 KiB
Markdown
87 lines
2.7 KiB
Markdown
#define-properties <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
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[![Build Status][travis-svg]][travis-url]
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[![dependency status][deps-svg]][deps-url]
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[![dev dependency status][dev-deps-svg]][dev-deps-url]
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[![License][license-image]][license-url]
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[![Downloads][downloads-image]][downloads-url]
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[![npm badge][npm-badge-png]][package-url]
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[![browser support][testling-svg]][testling-url]
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Define multiple non-enumerable properties at once. Uses `Object.defineProperty` when available; falls back to standard assignment in older engines.
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Existing properties are not overridden. Accepts a map of property names to a predicate that, when true, force-overrides.
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## Example
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```js
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var define = require('define-properties');
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var assert = require('assert');
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var obj = define({ a: 1, b: 2 }, {
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a: 10,
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b: 20,
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c: 30
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});
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assert(obj.a === 1);
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assert(obj.b === 2);
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assert(obj.c === 30);
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if (define.supportsDescriptors) {
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assert.deepEqual(Object.keys(obj), ['a', 'b']);
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assert.deepEqual(Object.getOwnPropertyDescriptor(obj, 'c'), {
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configurable: true,
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enumerable: false,
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value: 30,
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writable: false
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});
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}
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```
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Then, with predicates:
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```js
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var define = require('define-properties');
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var assert = require('assert');
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var obj = define({ a: 1, b: 2, c: 3 }, {
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a: 10,
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b: 20,
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c: 30
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}, {
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a: function () { return false; },
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b: function () { return true; }
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});
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assert(obj.a === 1);
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assert(obj.b === 20);
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assert(obj.c === 3);
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if (define.supportsDescriptors) {
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assert.deepEqual(Object.keys(obj), ['a', 'c']);
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assert.deepEqual(Object.getOwnPropertyDescriptor(obj, 'b'), {
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configurable: true,
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enumerable: false,
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value: 20,
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writable: false
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});
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}
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```
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## Tests
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Simply clone the repo, `npm install`, and run `npm test`
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[package-url]: https://npmjs.org/package/define-properties
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[npm-version-svg]: http://versionbadg.es/ljharb/define-properties.svg
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[travis-svg]: https://travis-ci.org/ljharb/define-properties.svg
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[travis-url]: https://travis-ci.org/ljharb/define-properties
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[deps-svg]: https://david-dm.org/ljharb/define-properties.svg
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[deps-url]: https://david-dm.org/ljharb/define-properties
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[dev-deps-svg]: https://david-dm.org/ljharb/define-properties/dev-status.svg
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[dev-deps-url]: https://david-dm.org/ljharb/define-properties#info=devDependencies
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[testling-svg]: https://ci.testling.com/ljharb/define-properties.png
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[testling-url]: https://ci.testling.com/ljharb/define-properties
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[npm-badge-png]: https://nodei.co/npm/define-properties.png?downloads=true&stars=true
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[license-image]: http://img.shields.io/npm/l/define-properties.svg
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[license-url]: LICENSE
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[downloads-image]: http://img.shields.io/npm/dm/define-properties.svg
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[downloads-url]: http://npm-stat.com/charts.html?package=define-properties
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