42 lines
1.4 KiB
JavaScript
42 lines
1.4 KiB
JavaScript
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var baseAssignValue = require('./_baseAssignValue'),
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createAggregator = require('./_createAggregator');
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/** Used for built-in method references. */
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var objectProto = Object.prototype;
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/** Used to check objects for own properties. */
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var hasOwnProperty = objectProto.hasOwnProperty;
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/**
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* Creates an object composed of keys generated from the results of running
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* each element of `collection` thru `iteratee`. The order of grouped values
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* is determined by the order they occur in `collection`. The corresponding
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* value of each key is an array of elements responsible for generating the
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* key. The iteratee is invoked with one argument: (value).
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*
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* @static
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* @memberOf _
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* @since 0.1.0
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* @category Collection
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* @param {Array|Object} collection The collection to iterate over.
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* @param {Function} [iteratee=_.identity] The iteratee to transform keys.
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* @returns {Object} Returns the composed aggregate object.
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* @example
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*
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* _.groupBy([6.1, 4.2, 6.3], Math.floor);
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* // => { '4': [4.2], '6': [6.1, 6.3] }
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*
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* // The `_.property` iteratee shorthand.
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* _.groupBy(['one', 'two', 'three'], 'length');
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* // => { '3': ['one', 'two'], '5': ['three'] }
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*/
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var groupBy = createAggregator(function(result, value, key) {
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if (hasOwnProperty.call(result, key)) {
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result[key].push(value);
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} else {
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baseAssignValue(result, key, [value]);
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}
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});
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module.exports = groupBy;
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