/**
 * Fast method
 */
function shift(arr, direction, n) {
   var times = n > arr.length ? n % arr.length : n;
   return arr.concat(arr.splice(0, (direction > 0 ? arr.length - times : times)));
}

/**
 * Slow method
 */
function shift2(arr, direction, n) {
   for (var i = n; i > 0; --i) { (direction > 0 ? arr.unshift(arr.pop()) : arr.push(arr.shift())); }
   return arr;
}