1 | 'use strict';
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2 | var uncurryThis = require('../internals/function-uncurry-this');
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3 | var aCallable = require('../internals/a-callable');
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4 | var isNullOrUndefined = require('../internals/is-null-or-undefined');
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5 | var lengthOfArrayLike = require('../internals/length-of-array-like');
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6 | var toObject = require('../internals/to-object');
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7 | var MapHelpers = require('../internals/map-helpers');
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8 | var iterate = require('../internals/map-iterate');
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9 |
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10 | var Map = MapHelpers.Map;
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11 | var mapHas = MapHelpers.has;
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12 | var mapSet = MapHelpers.set;
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13 | var push = uncurryThis([].push);
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14 |
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15 |
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16 |
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17 | module.exports = function uniqueBy(resolver) {
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18 | var that = toObject(this);
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19 | var length = lengthOfArrayLike(that);
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20 | var result = [];
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21 | var map = new Map();
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22 | var resolverFunction = !isNullOrUndefined(resolver) ? aCallable(resolver) : function (value) {
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23 | return value;
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24 | };
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25 | var index, item, key;
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26 | for (index = 0; index < length; index++) {
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27 | item = that[index];
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28 | key = resolverFunction(item);
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29 | if (!mapHas(map, key)) mapSet(map, key, item);
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30 | }
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31 | iterate(map, function (value) {
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32 | push(result, value);
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33 | });
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34 | return result;
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35 | };
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