diff -r 000000000000 -r 6474c204b198 addon-sdk/source/lib/sdk/util/object.js --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/addon-sdk/source/lib/sdk/util/object.js Wed Dec 31 06:09:35 2014 +0100 @@ -0,0 +1,92 @@ +/* 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) { + Object.getOwnPropertyNames(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) 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 blacklisted 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;