const work = (() => {
  let workload = []
  let cursor = null

  setImmediate(async () => {
    while (true) {
      const workload = await next()

      // implement as much as possible outside the loop
      for (const { context, args, resolve, reject } of workload) {
        reject(new Error('not implemented'))
      }
    }
  })

  const next = () => new Promise(resolve => {
    cursor = () => {
      if (workload.length === 0) return
      cursor = null
      const nextWorkload = [...workload]
      workload = []
      resolve(nextWorkload)
    }
    cursor()
  })

  return function work (...args) {
    const context = this
    return new Promise((resolve, reject) => {
      workload.push({ context, args, resolve, reject })
      if (typeof cursor === 'function') cursor()
    })
  }
})()

work().then(console.log).catch(console.error)