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comparison: addon-sdk/source/lib/sdk/util/object.js
addon-sdk/source/lib/sdk/util/object.js
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| 1 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 4 | |
| 5 "use strict"; | |
| 6 | |
| 7 module.metadata = { | |
| 8 "stability": "unstable" | |
| 9 }; | |
| 10 | |
| 11 const { flatten } = require('./array'); | |
| 12 | |
| 13 /** | |
| 14 * Merges all the properties of all arguments into first argument. If two or | |
| 15 * more argument objects have own properties with the same name, the property | |
| 16 * is overridden, with precedence from right to left, implying, that properties | |
| 17 * of the object on the left are overridden by a same named property of the | |
| 18 * object on the right. | |
| 19 * | |
| 20 * Any argument given with "falsy" value - commonly `null` and `undefined` in | |
| 21 * case of objects - are skipped. | |
| 22 * | |
| 23 * @examples | |
| 24 * var a = { bar: 0, a: 'a' } | |
| 25 * var b = merge(a, { foo: 'foo', bar: 1 }, { foo: 'bar', name: 'b' }); | |
| 26 * b === a // true | |
| 27 * b.a // 'a' | |
| 28 * b.foo // 'bar' | |
| 29 * b.bar // 1 | |
| 30 * b.name // 'b' | |
| 31 */ | |
| 32 function merge(source) { | |
| 33 let descriptor = {}; | |
| 34 | |
| 35 // `Boolean` converts the first parameter to a boolean value. Any object is | |
| 36 // converted to `true` where `null` and `undefined` becames `false`. Therefore | |
| 37 // the `filter` method will keep only objects that are defined and not null. | |
| 38 Array.slice(arguments, 1).filter(Boolean).forEach(function onEach(properties) { | |
| 39 Object.getOwnPropertyNames(properties).forEach(function(name) { | |
| 40 descriptor[name] = Object.getOwnPropertyDescriptor(properties, name); | |
| 41 }); | |
| 42 }); | |
| 43 return Object.defineProperties(source, descriptor); | |
| 44 } | |
| 45 exports.merge = merge; | |
| 46 | |
| 47 /** | |
| 48 * Returns an object that inherits from the first argument and contains all the | |
| 49 * properties from all following arguments. | |
| 50 * `extend(source1, source2, source3)` is equivalent of | |
| 51 * `merge(Object.create(source1), source2, source3)`. | |
| 52 */ | |
| 53 function extend(source) { | |
| 54 let rest = Array.slice(arguments, 1); | |
| 55 rest.unshift(Object.create(source)); | |
| 56 return merge.apply(null, rest); | |
| 57 } | |
| 58 exports.extend = extend; | |
| 59 | |
| 60 function has(obj, key) obj.hasOwnProperty(key); | |
| 61 exports.has = has; | |
| 62 | |
| 63 function each(obj, fn) { | |
| 64 for (let key in obj) has(obj, key) && fn(obj[key], key, obj); | |
| 65 } | |
| 66 exports.each = each; | |
| 67 | |
| 68 /** | |
| 69 * Like `merge`, except no property descriptors are manipulated, for use | |
| 70 * with platform objects. Identical to underscore's `extend`. Useful for | |
| 71 * merging XPCOM objects | |
| 72 */ | |
| 73 function safeMerge(source) { | |
| 74 Array.slice(arguments, 1).forEach(function onEach (obj) { | |
| 75 for (let prop in obj) source[prop] = obj[prop]; | |
| 76 }); | |
| 77 return source; | |
| 78 } | |
| 79 exports.safeMerge = safeMerge; | |
| 80 | |
| 81 /* | |
| 82 * Returns a copy of the object without blacklisted properties | |
| 83 */ | |
| 84 function omit(source, ...values) { | |
| 85 let copy = {}; | |
| 86 let keys = flatten(values); | |
| 87 for (let prop in source) | |
| 88 if (!~keys.indexOf(prop)) | |
| 89 copy[prop] = source[prop]; | |
| 90 return copy; | |
| 91 } | |
| 92 exports.omit = omit; |
