Creates an array of elements split into groups the length of size.

chunk.js

// chunk
// Creates an array of elements split into groups the length of size.

const chunk = (input, size) => {
  return input.reduce((arr, item, idx) => {
    if (idx % size === 0) {
      return [...arr, [item]];
    } else {
      return [...arr.slice(0, -1), [...arr.slice(-1)[0], item]];
    }
  }, []);
}

const arr = chunk(['a', 'b', 'c', 'd'], 2);
console.log(arr) // [["a", "b"], ["c", "d"]]

const arr2 = chunk(['a', 'b', 'c', 'd'], 3);
console.log(arr2) // [["a", "b", "c"], ["d"]]

console.log([...['a', 'b'], 'c'])