Emit values of an array over time

replayer.js

export default function replayer(array, opts = {}, emit) {
  let idx = 0
  let timer

  return {
    start: next,
    stop: stop,
    reset: reset
  }

  function reset() {
    idx = 0
  }
  function stop() {
    clearTimeout(timer)
  }

  function next() {
    const last = idx === array.length - 1
    emit({
      type: 'item',
      index: idx,
      item: array[idx]
    })

    if (last && opts.infinite !== false) {
      return
    }

    idx = last ? 0 : idx + 1

    const wait = (typeof opts.wait === 'function') ? opts.wait(idx) : (opts.wait || 1000)

    timer = setTimeout(next, wait)
  }
}