var arrayAggregator = require('./_arrayAggregator'),
      baseAggregator = require('./_baseAggregator'),
      baseIteratee = require('./_baseIteratee'),
      isArray = require('./isArray');
  
  /**
   * Creates a function like `_.groupBy`.
   *
   * @private
   * @param {Function} setter The function to set accumulator values.
   * @param {Function} [initializer] The accumulator object initializer.
   * @returns {Function} Returns the new aggregator function.
   */
  function createAggregator(setter, initializer) {
    return function(collection, iteratee) {
      var func = isArray(collection) ? arrayAggregator : baseAggregator,
          accumulator = initializer ? initializer() : {};
  
      return func(collection, setter, baseIteratee(iteratee, 2), accumulator);
    };
  }
  
  module.exports = createAggregator;