array chunks

array-chunks.js

// Using Array.prototype.reduce:
const getChunks = (array, size) => {
  return array.reduce((acc, curr, i) => {
    const pos = Math.floor(i/size);
    acc[pos] = [...(acc[pos]||[]), curr]; 
    return acc
  }, [])
}

// Using Array.from:
const getChunks = (array, size) => {
  const length = Math.ceil(array.length / size)
  return Array.from({ length }, (_v, i) => array.slice(i * size, (i * size) + size));
}

// Using a copy of the array and Array.prototype.splice:
const getChunks = (array, size) => {
  const a = [...array], result = []
  while(a.length > 0) {
    result.push(a.splice(0, size))
  }
  return result
}

/*
getChunks([1,2,3,4,5,6,7,8,9,0], 3)
(4) [Array(3), Array(3), Array(3), Array(1)]
0: (3) [1, 2, 3]
1: (3) [4, 5, 6]
2: (3) [7, 8, 9]
3: [0]
*/