如何处理在redux传奇中调用不同功能的多个动作？

Question

Here an example which is going to be easier to understand.

 function* a() { yield takeEvery(action.LOGIN_SUCCESS, b) } function* b() { yield takeEvery(action.FETCH_SUCCESS, c) } function* c() { yield console.log('action from function a') } function* d() { yield takeEvery(action.FETCH_SUCCESS, e) } function* e() { yield console.log('action from function d') } yield all([ fork(a), fork(d), ]) 

If LOGIN_SUCCESS happens then function b starts waiting for FETCH_SUCCESS. At the same time, function d is waiting for FETCH_SUCCESS.

The question is: how can I stop function d from running after the takeEvery in function a takes the LOGIN_SUCCESS and then FETCH_SUCCESS action?

In this case I want only function c to be called. Instead, what happens is that both function c and function e are called because FETCH_SUCCESS happens.

The idea is that I would like to have something in redux saga which remembers the previous action taken by the previous generator so that I can distinguish two different paths:

1) LOGIN_SUCCESS -> FETCH_SUCCESS -> function c

2) FETCH_SUCCESS -> function e

Hope I have been clear enough :)

Answer 1

How about modifying saga d like so:

function* d() {
  const task = yield takeEvery(action.FETCH_SUCCESS, e)
  yield take(action.LOGIN_SUCCESS)
  yield cancel(task)
}

This will kill the takeEvery in saga d once LOGIN_SUCCESS is dispatched.

Since you are using takeEvery for LOGIN_SUCCESS I assume it is something that can happen multiple times. In that case you will probably want to run another saga d on logout.