Function forEachOf

lib/utils.js:728–730

* @param {Array} arr * @param {Function} fn * @param {Function} [callback]

(arr, fn, callback)

 * @param {Function} [callback]
 */
function forEachOf(arr, fn, callback) {
  return mapEach(arr, fn, true, callback);
}

/**
 * @param {Array} arr