Dictionary permutation generator

Permutate.js

// console.log([...permutate(['1', '2', '3'], 2)])
// console.log([...permutate(['1', '2', '3'], 3)])

function* permutate(items, count) {
  yield* req([])

  function* req(array) {
    if (array.length == count) {
      yield array.join('')
      return
    }
    for (const item of items) {
      yield* req(array.concat(item))
    }
  }