How to create setTimeout loop for yield put()

Question

I have a saga watcher:

function* watchSetRefreshInterval() {
    yield takeLatest(SET_LOOP, setLoop);
}

and a setLoop saga

function* setLoop() {
        yield put({type: ANOTHER_WATCHER });
}

I want yield put({type: ANOTHER_WATCHER }); to happen with interval

This does not work

setTimeout(function timeoutFn(){
        yield put({type: ANOTHER_WATCHER });
        setTimeout(timeoutFn, 5000);
}, 5000);

You cannot use yield in non-generator function, making timeoutFn a generator does not work as well.

How can I call yield put in an interval. I don't want to use

while(true) {
        yield delay(5000);
        yield put({type: ANOTHER_WATCHER });
}

I want to use setTimeout function.

Answer 1

What you want is a classic example of an Event Channel.

Check out the link below -

https://redux-saga.js.org/docs/advanced/Channels.html

Sample-

import { eventChannel, END } from 'redux-saga'

function countdown(secs) {
  return eventChannel(emitter => {
      const iv = setInterval(() => {
        secs -= 1
        if (secs > 0) {
          emitter(secs)
        } else {
          // this causes the channel to close
          emitter(END)
        }
      }, 1000);
      // The subscriber must return an unsubscribe function
      return () => {
        clearInterval(iv)
      }
    }
  )
}

Hope this helps! 😇