chunk

chunk.js

function chunk(array, chunkSize) {
  if (!chunkSize) throw new Error('chunkSize must be greater than 0')
  return array.reduce((chunked, value, i) => {
    if (!(i % chunkSize)) chunked.push([])
    chunked[chunked.length - 1].push(value)
    return chunked
  }, [])
}