arrayReduce.js

/**
 * A specialized version of `_.reduce` for arrays without support for callback
 * shorthands and `this` binding.
 *
 * @private
 * @param {Array} array The array to iterate over.
 * @param {Function} iteratee The function invoked per iteration.
 * @param {*} [accumulator] The initial value.
 * @param {boolean} [initFromArray] Specify using the first element of `array`
 *  as the initial value.
 * @returns {*} Returns the accumulated value.
 */
function arrayReduce(array, iteratee, accumulator, initFromArray) {
  var index = -1,
      length = array.length;

  if (initFromArray && length) {
    accumulator = array[++index];
  }
  while (++index < length) {
    accumulator = iteratee(accumulator, array[index], index, array);
  }
  return accumulator;
}

module.exports = arrayReduce;