baseReduce.js 1.03 KB
define([], function() {

  /**
   * The base implementation of `_.reduce` and `_.reduceRight` without support
   * for callback shorthands and `this` binding, which iterates over `collection`
   * using the provided `eachFunc`.
   *
   * @private
   * @param {Array|Object|string} collection The collection to iterate over.
   * @param {Function} iteratee The function invoked per iteration.
   * @param {*} accumulator The initial value.
   * @param {boolean} initFromCollection Specify using the first or last element
   *  of `collection` as the initial value.
   * @param {Function} eachFunc The function to iterate over `collection`.
   * @returns {*} Returns the accumulated value.
   */
  function baseReduce(collection, iteratee, accumulator, initFromCollection, eachFunc) {
    eachFunc(collection, function(value, index, collection) {
      accumulator = initFromCollection
        ? (initFromCollection = false, value)
        : iteratee(accumulator, value, index, collection);
    });
    return accumulator;
  }

  return baseReduce;
});