| 1 | 'use strict';
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| 2 | var $ = require('../internals/export');
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| 3 | var aMap = require('../internals/a-map');
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| 4 | var MapHelpers = require('../internals/map-helpers');
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| 5 |
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| 6 | var get = MapHelpers.get;
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| 7 | var has = MapHelpers.has;
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| 8 | var set = MapHelpers.set;
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| 9 |
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| 10 | // `Map.prototype.emplace` method
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| 11 | // https://github.com/tc39/proposal-upsert
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| 12 | $({ target: 'Map', proto: true, real: true, forced: true }, {
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| 13 | emplace: function emplace(key, handler) {
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| 14 | var map = aMap(this);
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| 15 | var value, inserted;
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| 16 | if (has(map, key)) {
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| 17 | value = get(map, key);
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| 18 | if ('update' in handler) {
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| 19 | value = handler.update(value, key, map);
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| 20 | set(map, key, value);
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| 21 | } return value;
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| 22 | }
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| 23 | inserted = handler.insert(key, map);
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| 24 | set(map, key, inserted);
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| 25 | return inserted;
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| 26 | }
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| 27 | });
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