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- 'use strict';
- var $ = require('../internals/export');
- var aMap = require('../internals/a-map');
- var MapHelpers = require('../internals/map-helpers');
-
- var get = MapHelpers.get;
- var has = MapHelpers.has;
- var set = MapHelpers.set;
-
- // `Map.prototype.emplace` method
- // https://github.com/tc39/proposal-upsert
- $({ target: 'Map', proto: true, real: true, forced: true }, {
- emplace: function emplace(key, handler) {
- var map = aMap(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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