playing with callbags

callbags.ts

enum Type {
  START,
  DATA,
  END
}

type Callbag = (type: Type, payload: any) => void;

const producer: Callbag = (type, payload) => {
  if (type === Type.START) {
    const consumer = payload
    let i = 0;
    let handle;
    consumer(Type.START, (t, p) => {
      if (t === Type.END) clearInterval(handle)
      if (t === Type.DATA) i = p
    })
    handle = setInterval(() => {
      consumer(Type.DATA, i++)
    }, 1000)
  }
}

const consumer: Callbag = (type, payload) => {
  if (type === Type.START) {
    const cb = payload;
    setTimeout(() => { cb(Type.DATA, 17) }, 3100)
    setTimeout(() => { cb(Type.END) }, 7100)
  } else if (type === Type.DATA) {
    console.log(payload)
  }
}

producer(Type.START, consumer)