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/* 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 create = Object.create;
const prototypeOf = Object.getPrototypeOf;
/**
* Returns a new namespace, function that may can be used to access an
* namespaced object of the argument argument. Namespaced object are associated
* with owner objects via weak references. Namespaced objects inherit from the
* owners ancestor namespaced object. If owner's ancestor is `null` then
* namespaced object inherits from given `prototype`. Namespaces can be used
* to define internal APIs that can be shared via enclosing `namespace`
* function.
* @examples
* const internals = ns();
* internals(object).secret = secret;
*/
function ns() {
const map = new WeakMap();
return function namespace(target) {
if (!target) // If `target` is not an object return `target` itself.
return target;
// If target has no namespaced object yet, create one that inherits from
// the target prototype's namespaced object.
if (!map.has(target))
map.set(target, create(namespace(prototypeOf(target) || null)));
return map.get(target);
};
};
// `Namespace` is a e4x function in the scope, so we export the function also as
// `ns` as alias to avoid clashing.
exports.ns = ns;
exports.Namespace = ns;
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