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author | Matt A. Tobin <email@mattatobin.com> | 2018-02-10 02:51:36 -0500 |
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committer | Matt A. Tobin <email@mattatobin.com> | 2018-02-10 02:51:36 -0500 |
commit | 37d5300335d81cecbecc99812747a657588c63eb (patch) | |
tree | 765efa3b6a56bb715d9813a8697473e120436278 /toolkit/jetpack/sdk/util/object.js | |
parent | b2bdac20c02b12f2057b9ef70b0a946113a00e00 (diff) | |
parent | 4fb11cd5966461bccc3ed1599b808237be6b0de9 (diff) | |
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Merge branch 'ext-work'
Diffstat (limited to 'toolkit/jetpack/sdk/util/object.js')
-rw-r--r-- | toolkit/jetpack/sdk/util/object.js | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/toolkit/jetpack/sdk/util/object.js b/toolkit/jetpack/sdk/util/object.js new file mode 100644 index 000000000..9d202bb51 --- /dev/null +++ b/toolkit/jetpack/sdk/util/object.js @@ -0,0 +1,104 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ +"use strict"; + +module.metadata = { + "stability": "unstable" +}; + +const { flatten } = require('./array'); + +/** + * Merges all the properties of all arguments into first argument. If two or + * more argument objects have own properties with the same name, the property + * is overridden, with precedence from right to left, implying, that properties + * of the object on the left are overridden by a same named property of the + * object on the right. + * + * Any argument given with "falsy" value - commonly `null` and `undefined` in + * case of objects - are skipped. + * + * @examples + * var a = { bar: 0, a: 'a' } + * var b = merge(a, { foo: 'foo', bar: 1 }, { foo: 'bar', name: 'b' }); + * b === a // true + * b.a // 'a' + * b.foo // 'bar' + * b.bar // 1 + * b.name // 'b' + */ +function merge(source) { + let descriptor = {}; + + // `Boolean` converts the first parameter to a boolean value. Any object is + // converted to `true` where `null` and `undefined` becames `false`. Therefore + // the `filter` method will keep only objects that are defined and not null. + Array.slice(arguments, 1).filter(Boolean).forEach(function onEach(properties) { + getOwnPropertyIdentifiers(properties).forEach(function(name) { + descriptor[name] = Object.getOwnPropertyDescriptor(properties, name); + }); + }); + return Object.defineProperties(source, descriptor); +} +exports.merge = merge; + +/** + * Returns an object that inherits from the first argument and contains all the + * properties from all following arguments. + * `extend(source1, source2, source3)` is equivalent of + * `merge(Object.create(source1), source2, source3)`. + */ +function extend(source) { + let rest = Array.slice(arguments, 1); + rest.unshift(Object.create(source)); + return merge.apply(null, rest); +} +exports.extend = extend; + +function has(obj, key) { + return obj.hasOwnProperty(key); +} +exports.has = has; + +function each(obj, fn) { + for (let key in obj) has(obj, key) && fn(obj[key], key, obj); +} +exports.each = each; + +/** + * Like `merge`, except no property descriptors are manipulated, for use + * with platform objects. Identical to underscore's `extend`. Useful for + * merging XPCOM objects + */ +function safeMerge(source) { + Array.slice(arguments, 1).forEach(function onEach (obj) { + for (let prop in obj) source[prop] = obj[prop]; + }); + return source; +} +exports.safeMerge = safeMerge; + +/* + * Returns a copy of the object without omitted properties + */ +function omit(source, ...values) { + let copy = {}; + let keys = flatten(values); + for (let prop in source) + if (!~keys.indexOf(prop)) + copy[prop] = source[prop]; + return copy; +} +exports.omit = omit; + +// get object's own property Symbols and/or Names, including nonEnumerables by default +function getOwnPropertyIdentifiers(object, options = { names: true, symbols: true, nonEnumerables: true }) { + const symbols = !options.symbols ? [] : + Object.getOwnPropertySymbols(object); + const names = !options.names ? [] : + options.nonEnumerables ? Object.getOwnPropertyNames(object) : + Object.keys(object); + return [...names, ...symbols]; +} +exports.getOwnPropertyIdentifiers = getOwnPropertyIdentifiers; |