gistfile1.js

var shuffle = function (arr) {
  //check to make sure we were not passed an empty value.
  if (!arr) {
    console.error('Target of shuffling cannot be empty.');
    return false;
  }
  //check to make sure the value we were passed is an Array
  if (arr.constructor != Array) {
    console.error('Target of shuffling must be of type Array');
    return false;
  }

  var result = [];

  //as long as the array has a length keep running.
  while (arr.length) {
    //we will push a random number between 0 and the given array's length - 1 to account for
    //arrays starting at 0. Splice returns an array so we will pop the element out of
    //that array by pulling it out of the original array and pushing it to the result array.
    //This technique is similar to the Fischer-Yates shuffling technique.
    result.push(arr.splice(_.random(0, arr.length - 1), 1).pop())
  }

  return result;
}