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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; } });
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