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| 'use strict';
| var $ = require('../internals/export');
| var aWeakMap = require('../internals/a-weak-map');
| var WeakMapHelpers = require('../internals/weak-map-helpers');
|
| var get = WeakMapHelpers.get;
| var has = WeakMapHelpers.has;
| var set = WeakMapHelpers.set;
|
| // `WeakMap.prototype.emplace` method
| // https://github.com/tc39/proposal-upsert
| $({ target: 'WeakMap', proto: true, real: true, forced: true }, {
| emplace: function emplace(key, handler) {
| var map = aWeakMap(this);
| var value, inserted;
| if (has(map, key)) {
| value = get(map, key);
| if ('update' in handler) {
| value = handler.update(value, key, map);
| set(map, key, value);
| } return value;
| }
| inserted = handler.insert(key, map);
| set(map, key, inserted);
| return inserted;
| }
| });
|
|
