| 1 | # define-properties <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
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| 2 |
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| 3 | [![github actions][actions-image]][actions-url]
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| 4 | [![coverage][codecov-image]][codecov-url]
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| 5 | [![dependency status][deps-svg]][deps-url]
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| 6 | [![dev dependency status][dev-deps-svg]][dev-deps-url]
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| 7 | [![License][license-image]][license-url]
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| 8 | [![Downloads][downloads-image]][downloads-url]
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| 9 |
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| 10 | [![npm badge][npm-badge-png]][package-url]
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| 11 |
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| 12 | Define multiple non-enumerable properties at once. Uses `Object.defineProperty` when available; falls back to standard assignment in older engines.
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| 13 | Existing properties are not overridden. Accepts a map of property names to a predicate that, when true, force-overrides.
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| 14 |
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| 15 | ## Example
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| 16 |
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| 17 | ```js
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| 18 | var define = require('define-properties');
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| 19 | var assert = require('assert');
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| 20 |
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| 21 | var obj = define({ a: 1, b: 2 }, {
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| 22 | a: 10,
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| 23 | b: 20,
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| 24 | c: 30
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| 25 | });
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| 26 | assert(obj.a === 1);
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| 27 | assert(obj.b === 2);
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| 28 | assert(obj.c === 30);
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| 29 | if (define.supportsDescriptors) {
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| 30 | assert.deepEqual(Object.keys(obj), ['a', 'b']);
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| 31 | assert.deepEqual(Object.getOwnPropertyDescriptor(obj, 'c'), {
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| 32 | configurable: true,
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| 33 | enumerable: false,
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| 34 | value: 30,
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| 35 | writable: false
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| 36 | });
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| 37 | }
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| 38 | ```
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| 39 |
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| 40 | Then, with predicates:
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| 41 | ```js
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| 42 | var define = require('define-properties');
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| 43 | var assert = require('assert');
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| 44 |
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| 45 | var obj = define({ a: 1, b: 2, c: 3 }, {
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| 46 | a: 10,
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| 47 | b: 20,
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| 48 | c: 30
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| 49 | }, {
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| 50 | a: function () { return false; },
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| 51 | b: function () { return true; }
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| 52 | });
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| 53 | assert(obj.a === 1);
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| 54 | assert(obj.b === 20);
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| 55 | assert(obj.c === 3);
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| 56 | if (define.supportsDescriptors) {
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| 57 | assert.deepEqual(Object.keys(obj), ['a', 'c']);
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| 58 | assert.deepEqual(Object.getOwnPropertyDescriptor(obj, 'b'), {
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| 59 | configurable: true,
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| 60 | enumerable: false,
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| 61 | value: 20,
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| 62 | writable: false
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| 63 | });
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| 64 | }
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| 65 | ```
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| 66 |
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| 67 | ## Tests
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| 68 | Simply clone the repo, `npm install`, and run `npm test`
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| 69 |
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| 70 | [package-url]: https://npmjs.org/package/define-properties
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| 71 | [npm-version-svg]: https://versionbadg.es/ljharb/define-properties.svg
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| 72 | [deps-svg]: https://david-dm.org/ljharb/define-properties.svg
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| 73 | [deps-url]: https://david-dm.org/ljharb/define-properties
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| 74 | [dev-deps-svg]: https://david-dm.org/ljharb/define-properties/dev-status.svg
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| 75 | [dev-deps-url]: https://david-dm.org/ljharb/define-properties#info=devDependencies
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| 76 | [npm-badge-png]: https://nodei.co/npm/define-properties.png?downloads=true&stars=true
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| 77 | [license-image]: https://img.shields.io/npm/l/define-properties.svg
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| 78 | [license-url]: LICENSE
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| 79 | [downloads-image]: https://img.shields.io/npm/dm/define-properties.svg
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| 80 | [downloads-url]: https://npm-stat.com/charts.html?package=define-properties
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| 81 | [codecov-image]: https://codecov.io/gh/ljharb/define-properties/branch/main/graphs/badge.svg
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| 82 | [codecov-url]: https://app.codecov.io/gh/ljharb/define-properties/
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| 83 | [actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/define-properties
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| 84 | [actions-url]: https://github.com/ljharb/define-properties/actions
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