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comparison: addon-sdk/source/lib/sdk/core/namespace.js
addon-sdk/source/lib/sdk/core/namespace.js
- changeset 0
- 6474c204b198
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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 create = Object.create; | |
| 12 const prototypeOf = Object.getPrototypeOf; | |
| 13 | |
| 14 /** | |
| 15 * Returns a new namespace, function that may can be used to access an | |
| 16 * namespaced object of the argument argument. Namespaced object are associated | |
| 17 * with owner objects via weak references. Namespaced objects inherit from the | |
| 18 * owners ancestor namespaced object. If owner's ancestor is `null` then | |
| 19 * namespaced object inherits from given `prototype`. Namespaces can be used | |
| 20 * to define internal APIs that can be shared via enclosing `namespace` | |
| 21 * function. | |
| 22 * @examples | |
| 23 * const internals = ns(); | |
| 24 * internals(object).secret = secret; | |
| 25 */ | |
| 26 function ns() { | |
| 27 const map = new WeakMap(); | |
| 28 return function namespace(target) { | |
| 29 if (!target) // If `target` is not an object return `target` itself. | |
| 30 return target; | |
| 31 // If target has no namespaced object yet, create one that inherits from | |
| 32 // the target prototype's namespaced object. | |
| 33 if (!map.has(target)) | |
| 34 map.set(target, create(namespace(prototypeOf(target) || null))); | |
| 35 | |
| 36 return map.get(target); | |
| 37 }; | |
| 38 }; | |
| 39 | |
| 40 // `Namespace` is a e4x function in the scope, so we export the function also as | |
| 41 // `ns` as alias to avoid clashing. | |
| 42 exports.ns = ns; | |
| 43 exports.Namespace = ns; |
