1
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var baseAssignValue = require('./_baseAssignValue'),
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2
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createAggregator = require('./_createAggregator');
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3
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4
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/** Used for built-in method references. */
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5
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var objectProto = Object.prototype;
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6
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7
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/** Used to check objects for own properties. */
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8
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var hasOwnProperty = objectProto.hasOwnProperty;
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9
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10
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/**
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11
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* Creates an object composed of keys generated from the results of running
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12
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* each element of `collection` thru `iteratee`. The order of grouped values
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13
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* is determined by the order they occur in `collection`. The corresponding
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14
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* value of each key is an array of elements responsible for generating the
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15
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* key. The iteratee is invoked with one argument: (value).
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16
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*
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17
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* @static
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18
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* @memberOf _
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19
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* @since 0.1.0
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20
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* @category Collection
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21
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* @param {Array|Object} collection The collection to iterate over.
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22
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* @param {Function} [iteratee=_.identity] The iteratee to transform keys.
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23
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* @returns {Object} Returns the composed aggregate object.
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24
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* @example
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25
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*
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26
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* _.groupBy([6.1, 4.2, 6.3], Math.floor);
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27
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* // => { '4': [4.2], '6': [6.1, 6.3] }
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28
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*
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29
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* // The `_.property` iteratee shorthand.
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30
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* _.groupBy(['one', 'two', 'three'], 'length');
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31
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* // => { '3': ['one', 'two'], '5': ['three'] }
|
32
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*/
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33
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var groupBy = createAggregator(function(result, value, key) {
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34
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if (hasOwnProperty.call(result, key)) {
|
35
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result[key].push(value);
|
36
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} else {
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37
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baseAssignValue(result, key, [value]);
|
38
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}
|
39
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});
|
40
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|
41
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module.exports = groupBy;
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