Utility function to create a new array with elements being initialized by calling an initializer

index.js

/**
 * Create an array by calling an initializer on each element
 *
 * @param length {Number} length of the created array
 * @param init {Function} callback to call on each element of the array
 */
function array(length, init = index => 0) {
  return Array.apply(null, { length }).map(Function.call, init)
}