Write a function that splits an array (first argument) into groups the length of size (second argument) and returns them as a two-dimensional array.

chunk.js

function chunk(arr, size) {
  var results = [];
  while(arr.length){
    results.push(arr.splice(0,size));
  }
  return results;
}

chunk(["a", "b", "c", "d"], 2);