summaryrefslogtreecommitdiff
path: root/tools/eslint/node_modules/lodash/groupBy.js
blob: ae7db5faa354ae7bc0d45ba0da50b26915048b75 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
var createAggregator = require('./_createAggregator');

/** Used for built-in method references. */
var objectProto = Object.prototype;

/** Used to check objects for own properties. */
var hasOwnProperty = objectProto.hasOwnProperty;

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

module.exports = groupBy;