1#define-properties <sup>[![Version Badge][npm-version-svg]][package-url]</sup> 2 3[![Build Status][travis-svg]][travis-url] 4[![dependency status][deps-svg]][deps-url] 5[![dev dependency status][dev-deps-svg]][dev-deps-url] 6[![License][license-image]][license-url] 7[![Downloads][downloads-image]][downloads-url] 8 9[![npm badge][npm-badge-png]][package-url] 10 11[![browser support][testling-svg]][testling-url] 12 13Define multiple non-enumerable properties at once. Uses `Object.defineProperty` when available; falls back to standard assignment in older engines. 14Existing properties are not overridden. Accepts a map of property names to a predicate that, when true, force-overrides. 15 16## Example 17 18```js 19var define = require('define-properties'); 20var assert = require('assert'); 21 22var obj = define({ a: 1, b: 2 }, { 23 a: 10, 24 b: 20, 25 c: 30 26}); 27assert(obj.a === 1); 28assert(obj.b === 2); 29assert(obj.c === 30); 30if (define.supportsDescriptors) { 31 assert.deepEqual(Object.keys(obj), ['a', 'b']); 32 assert.deepEqual(Object.getOwnPropertyDescriptor(obj, 'c'), { 33 configurable: true, 34 enumerable: false, 35 value: 30, 36 writable: false 37 }); 38} 39``` 40 41Then, with predicates: 42```js 43var define = require('define-properties'); 44var assert = require('assert'); 45 46var obj = define({ a: 1, b: 2, c: 3 }, { 47 a: 10, 48 b: 20, 49 c: 30 50}, { 51 a: function () { return false; }, 52 b: function () { return true; } 53}); 54assert(obj.a === 1); 55assert(obj.b === 20); 56assert(obj.c === 3); 57if (define.supportsDescriptors) { 58 assert.deepEqual(Object.keys(obj), ['a', 'c']); 59 assert.deepEqual(Object.getOwnPropertyDescriptor(obj, 'b'), { 60 configurable: true, 61 enumerable: false, 62 value: 20, 63 writable: false 64 }); 65} 66``` 67 68## Tests 69Simply clone the repo, `npm install`, and run `npm test` 70 71[package-url]: https://npmjs.org/package/define-properties 72[npm-version-svg]: http://versionbadg.es/ljharb/define-properties.svg 73[travis-svg]: https://travis-ci.org/ljharb/define-properties.svg 74[travis-url]: https://travis-ci.org/ljharb/define-properties 75[deps-svg]: https://david-dm.org/ljharb/define-properties.svg 76[deps-url]: https://david-dm.org/ljharb/define-properties 77[dev-deps-svg]: https://david-dm.org/ljharb/define-properties/dev-status.svg 78[dev-deps-url]: https://david-dm.org/ljharb/define-properties#info=devDependencies 79[testling-svg]: https://ci.testling.com/ljharb/define-properties.png 80[testling-url]: https://ci.testling.com/ljharb/define-properties 81[npm-badge-png]: https://nodei.co/npm/define-properties.png?downloads=true&stars=true 82[license-image]: http://img.shields.io/npm/l/define-properties.svg 83[license-url]: LICENSE 84[downloads-image]: http://img.shields.io/npm/dm/define-properties.svg 85[downloads-url]: http://npm-stat.com/charts.html?package=define-properties 86 87
