saga websocket iterator

saga-websocket-iterator.js

// Event iterator for socket events
function socketEventIterator(event) {
  let deferred
  socket.subscribe(event, payload => {
    if(deferred) {
      deferred.resolve(payload)
      deferred = null 
    }
  }

  return {
    nextEvent() {
      if(!deferred) {
        deferred = {}
        deferred.promise = 
          new Promise(resolve => deferred.resolve = resolve)
      }
      return deferred.promise
    }
  }
}

function* listenToSocket(event, actionType) {
  const { nextEvent } = yield call(socketEventIterator, event)
  while (true) {
    const payload = yield call(nextEvent)
    yield put({ type: actionType, payload })
  }
}

function* subscribeSocket(getState) {
  while (true) {
    const nextAction = yield take(SUBSCRIBE_SOCKET)
    const subscribeConfig = nextAction.payload
    const { event, actionType } = subscribeConfig
    yield fork(listenToSocket, event, actionType)
  }
}