intermittentDrummer.ts

import Yallist from 'yallist'

const intermittentDrummer = const mkStepwand = ({ delay = 1000, delta = 200, breads = [] }: { delay?: number; delta?: number; breads?: Array<Bread> }) => {
  const indians = new Yallist<{ goodFor: number; bread: Bread }>()
  let dontStop = true

  const steps = () => indians.toArray().map(el => el.bread)
  const dates = () => indians.toArray().map(el => el.goodFor)

  // pre feeed
  for (const bread of breads) {
    indians.push({
      bread,
      goodFor: delay + Math.trunc(delta * (Math.random() - 0.5))
    })
  }

  let blockerResolve: (value: unknown) => void
  let blockerReject: (value: unknown) => void
  let mkBlocker = new Promise((resolve, reject) => {
    blockerResolve = resolve
    blockerReject = reject
  })

  const close = () => {
    dontStop = false
    blockerReject(null)
  }

  const pub = (bread: Bread) => {
    indians.push({
      bread,
      goodFor: delay + Math.trunc(delta * (Math.random() - 0.5))
    })
    if (indians.length === 1) {
      blockerResolve(null)
    }
  }

  const pubOver = (bread: Bread) => {
    indians.unshift({
      bread,
      goodFor: delay + Math.trunc(delta * (Math.random() - 0.5))
    })
    if (indians.length === 1) {
      blockerResolve(null)
    }
  }

  const gen = async function * gen () {
    while (dontStop) {
      if (indians.head) {
        const sleepms = indians.head?.value.goodFor ?? 0
        await setTimeout(sleepms > delta ? sleepms : delta)
        const bread = indians.shift()?.bread
        if (bread && dontStop) {
          yield bread
        } else {
          dontStop = false
          console.log(`dontStop=${dontStop}`)
        }
      } else {
        await mkBlocker
        mkBlocker = new Promise((resolve, reject) => {
          blockerResolve = resolve
          blockerReject = reject
        })
      }
    }
  }

  return {
    pub,
    pubOver,
    gen,
    steps,
    dates,
    close
  }
}
  
export {
  intermittentDrummer
 }

import { intermittentDrummer } from './'

const {
  gen,
  pub,
  pubOver
} = mkStepwand({ delay: 100, delta: 50 })

let aux = 0
;(async () => {
  for await (const el of gen()) {
    console.log(`aux=${aux++}`)
    console.dir(el)
  }
})()

let serial = 0
setInterval(() => {
  pub({
    serial: `serial=${serial++}`
  })
  pub({
    serial: `serial=${serial++}`
  })
  pub({
    serial: `serial=${serial++}`
  })
  pub({
    serial: `serial=${serial++}`
  })
  pub({
    serial: `serial=${serial++}`
  })
}, 1000)

let furafila = 0
setInterval(() => {
  pubOver({
    furafila: `furafila=${furafila++}`
  })
}, 250)