eachSlice bench

result

Test start!
chunkWhile x 2,882,663 ops/sec ±0.71% (86 runs sampled)
chunkRec x 2,601,506 ops/sec ±0.91% (86 runs sampled)
chunkReduce x 2,993,484 ops/sec ±0.89% (85 runs sampled)
Fastest is chunkReduce

test.js

const Benchmark = require('benchmark')

const chunkWhile = (array, size = 2) => {
  const result = []
  const tmp = [...array]
  while (tmp.length) {
    result.push(tmp.splice(0, size))
  }

  return result
}

const chunkRec = (array, size = 2, result = []) => {
  if (array.length === 0) {
    return result
  }
  result.push(array.splice(0, size))

  return chunkRec(array, size, result)
}

const chunkReduce = (array, size = 2) => {
    return array.reduce(
        (result, _, i) => (i % size ? result : [...result, array.slice(i, i + size)]),
        []
    )
}

const suite = new Benchmark.Suite

suite.on('start', () => {
  console.log('Test start!')
}).add('chunkWhile', () => {
  chunkWhile([1, 2, 3, 4, 5, 6], 2)
}).add('chunkRec', () => {
  chunkRec([1, 2, 3, 4, 5, 6], 2)
}).add('chunkReduce', () => {
  chunkReduce([1, 2, 3, 4, 5, 6], 2)
}).on('cycle', (event) => {
  console.log(String(event.target))
}).on('complete', function () {
  console.log(`Fastest is ${this.filter('fastest').map('name')}`)
}).run({ async: true })