38 a simple co(async generator function runner)

co.js

function sleep(ms, message) {
  return new Promise((resolve) => {
    setTimeout(() => {
      resolve(message)
    }, ms)
  })
}

function co(fn) {
  const generator = fn()
  function tick(nextVal) {
    return new Promise((resolve) => {
      const { value, done } = generator.next(nextVal)
      console.log(nextVal, 'nextVal')
      if (value?.then) {
        value.then((resolvedValue) => {
          resolve({ value: resolvedValue, done })
          tick(resolvedValue)
        })
      } else if (!done) {
        resolve({ value, done })
        return tick(value)
      }
    })
  }
  tick()
}

co(function*() {
  const result0 = yield Promise.all([
    sleep(1000, 'all1'),
    sleep(2000, 'all2')
  ])
  console.log(result0)
  const result1 = yield sleep(1000, 'res1')
  console.log(result1)
  const result2 = yield sleep(2000, 0)
  console.log(result2)
  const result3 = yield sleep(3000)
  console.log(result3)
})