Swap, insertBefore and insertAfter

ArrayUtils.js

var swap = function(arr, i, j){
  var temp = arr[i];
  arr[i] = arr[j];
  arr[j] = temp;
  return arr;
};
var insertBefore = function(arr, i, j){
  if(i == j || i == j - 1) return arr;
  else if(i < j) return insertBefore(swap(arr, i, i+1), i+1, j);
  else if(i > j) return insertBefore(swap(arr, i, i-1), i-1, j);
};
var insertAfter = function(arr, i, j){
  if(i == j || i == j + 1) return arr;
  else if(i < j) return insertAfter(swap(arr, i, i+1), i+1, j);
  else if(i > j) return insertAfter(swap(arr, i, i-1), i-1, j);
};