function chunkArrayInGroups(arr, size) {
  // Break it up.
  let newArr = [];
  let newarr2 = [];
  if(arr.length > size){
    for(let i = 0; i <= arr.length; i = i + size){
     newArr = (arr.slice(arr[i], arr[i + size]));
     newarr2.push(newArr)



  }
  }

  return newArr;
}

console.log(chunkArrayInGroups(["a", "b", "c", "d"], 2));