1  var arrayAggregator = require('./_arrayAggregator'),
 2      baseAggregator = require('./_baseAggregator'),
 3      baseIteratee = require('./_baseIteratee'),
 4      isArray = require('./isArray');
 5  
 6  /**
 7   * Creates a function like `_.groupBy`.
 8   *
 9   * @private
10   * @param {Function} setter The function to set accumulator values.
11   * @param {Function} [initializer] The accumulator object initializer.
12   * @returns {Function} Returns the new aggregator function.
13   */
14  function createAggregator(setter, initializer) {
15    return function(collection, iteratee) {
16      var func = isArray(collection) ? arrayAggregator : baseAggregator,
17          accumulator = initializer ? initializer() : {};
18  
19      return func(collection, setter, baseIteratee(iteratee, 2), accumulator);
20    };
21  }
22  
23  module.exports = createAggregator;