Merge Sort

var Mergesort = (function() {


  function sort(array) {

    var length = array.length,
        mid    = Math.floor(length * 0.5),
        left   = array.slice(0, mid),
        right  = array.slice(mid, length);

    if(length === 1) {
      return array;
    }

    return merge(sort(left), sort(right));

  }


  function merge(left, right) {

    var result = [];

    while(left.length || right.length) {

      if(left.length && right.length) {

        if(left[0] < right[0]) {
          result.push(left.shift());
        } else {
          result.push(right.shift());
        }

      } else if (left.length) {
        result.push(left.shift());
      } else {
        result.push(right.shift());
      }

    }

    return result;

  }

  return {
    sort: sort
  };

})();