[ Generators / Promises / Javascript / ES6 ]: Running generators synchronously in JS

simple.js

function run(generator) {
  let progress = generator()
  let step = progress.next()

  const iterate = (progress, { done, value }) => {
    const isArrayValue = Array.isArray(value)
    const invoke = (value) => {
      let complete = new Promise(resolve => {
        iterate(progress, progress.next(value)).then(resolve)
      })

      return complete
    }

    if (done) { return Promise.resolve(value) }

    return isArrayValue ? Promise.all(value.map(invoke)) : invoke(value)
  }

  iterate(progress, step)
}

const delay = (ms, phrase) => {
  return new Promise(resolve => setTimeout(() => console.log(phrase), ms))
}

run(function* () {
  yield [
    delay(100, "Heyyyyyy"),
    delay(200, "Youuuuu"),
    delay(300, "Guuuuyyyyyyyyyyyyys")
  ]
  yield delay(100, "Ha ha ha!")
})