JS: rotate array with N

index.js

/**
 * Write a function that takes an array of integers
   and returns that array rotated by N positions.
   For example, if N=2, given the input array [1, 2, 3, 4, 5, 6]
   the function should return [5, 6, 1, 2, 3, 4]
 */
var rotate = function (arr, n) {
  var L = arr.length;
  return arr.slice(L - n).concat(arr.slice(0, L - n));
};

console.assert( rotate( [1, 2, 3, 4, 5, 6] ), [5, 6, 1, 2, 3, 4] );

You didn't pass n in the example

Above Code fails for value of n >= 13. We must use n% arr.length for such cases.