rotate.js

/*  Rotate an array n positions 
 *  if n is positive - rotate to the left
 *  if n is negative - rotate to the right 
 */
 

Array.prototype.rotate = function(n) {
  //Make a copy of the current array 
  var newArray = this.slice(0);
  //Handle a number greater than the length so that it loops around
  if (n > this.length) n = (n/Math.abs(n)) * (n % this.length);
  var a = newArray.splice(n);
  return a.concat(newArray);
};


var a = [1,2,3,4,5,6];

var b = a.rotate(-2);
console.log(a);
console.log(b);