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