CODEWITHSUNDEEP
javascriptreactjsredux-saga
Tiến Nguyễn Hoàng
Tiến Nguyễn Hoàng

Reputation: 163

Redux-saga cannot use generator function inside promise?

I'm a newbie to redux-saga. Currently I'm working on a simple login example. Take a look at these function:

function sendLoginRequest(data) {
  const headers = { 'Accept': 'application/json' };
  const url = LOGIN_URL;
  const serialize = new FormData(data.event.target);
  const loginData = {
    username: serialize.get('email'),
    password: serialize.get('password'),
    client_secret: APP_SECRET_KEY,
    client_id: APP_SECRET_ID,
    grant_type: PASSWORD_GRANT_TYPE,
    scope: '*',
  }

  return axios({
    method: 'POST',
    url: url,
    data: loginData,
    headers: headers,
  });
}

export function* loginRequest(data) {
  yield takeLatest(LOGIN_REQUEST, data => {
    const response = sendLoginRequest(data);
    console.log(response);
    response
      .then(function* (data) {
        console.log(data);
        yield put(LOGIN_SUCCESS, data.data);
      })
      .catch(function* (err) {
        console.log(err);
        yield put(LOGIN_FAILURE, err.response);
      });
  });
}

It's work perfect if I run middleware like this:

const sagaMiddleware = createSagaMiddleware();
const store = createStore(
  rootReducer,
  applyMiddleware(sagaMiddleware)
);
sagaMiddleware.run(loginRequest);

But then I add a new rootSaga:

export default function* rootSaga() {
    yield all([
        fork(loginRequest),
        fork(loginSuccess),
    fork(loginFailure)
    ]);
}

And I run the rootSaga instead of loginRequest saga:

const sagaMiddleware = createSagaMiddleware();
const store = createStore(
  rootReducer,
  applyMiddleware(sagaMiddleware)
);
sagaMiddleware.run(rootSaga);

And now these new code doesn't work at all. when I try to console.log(response); in loginRequest generator function, it's shown that the promise has been resolved. And it doesn't run the then-catch.

Can anyone help me clear this out? Thank you~

Upvotes: 0

Views: 1671

Answers (1)

tpdietz
tpdietz

Reputation: 1368

Please try this:

export function* loginRequest(data) {
  yield takeLatest(LOGIN_REQUEST, data => {
    const response = yield call(sendLoginRequest, data);

    if (response.status >= 200 && response.status < 300) {
        yield put(LOGIN_SUCCESS, data.data);
        return;
    }
    yield put(LOGIN_FAILURE, err.response);
  });
}

The thing to note is sendLoginRequest returns a promise. redux-saga is designed to work with promises without using .then(). You can yield call() any function that returns a promise and redux-saga will wait for the promise to resolve before executing the next line of code.

Upvotes: 3

Related Questions