1 var baseCallback = require('./baseCallback'),
2 baseEach = require('./baseEach'),
3 isArray = require('../lang/isArray');
6 * Creates a `_.countBy`, `_.groupBy`, `_.indexBy`, or `_.partition` function.
9 * @param {Function} setter The function to set keys and values of the accumulator object.
10 * @param {Function} [initializer] The function to initialize the accumulator object.
11 * @returns {Function} Returns the new aggregator function.
13 function createAggregator(setter, initializer) {
14 return function(collection, iteratee, thisArg) {
15 var result = initializer ? initializer() : {};
16 iteratee = baseCallback(iteratee, thisArg, 3);
18 if (isArray(collection)) {
20 length = collection.length;
22 while (++index < length) {
23 var value = collection[index];
24 setter(result, value, iteratee(value, index, collection), collection);
27 baseEach(collection, function(value, key, collection) {
28 setter(result, value, iteratee(value, key, collection), collection);
35 module.exports = createAggregator;