title: What is the proper way of connecting firebase with redux-sagas?
body: <p>I am building react-native app, where I use <code>react-native-firebase</code> and <code>redux-saga</code>. This is my first project using <code>redux-saga</code>, hence I am learning. So far I got the authentication of the user using the following:</p>
  
  <pre><code>import firebase from 'react-native-firebase';
  
  function* loginEmlPwdSaga(action) {
    try {
      const auth = firebase.auth();
      const data = yield call(
        [auth, auth.signInAndRetrieveDataWithEmailAndPassword],
        action.email,
        action.password,
      );
      yield put(loginSuccess(data));
    } catch (error) {
      yield put(loginFail(error));
    }
  }
  </code></pre>
  
  <p>However, now I am stuck at the point, where I want to subscribe to the collection. In <code>react-native-firebase</code> I would use the following:</p>
  
  <pre><code>firebase.firestore().collection('users').onSnapshot(...)
  </code></pre>
  
  <p>I am not sure what is the best approach to handle subscribes in <code>redux-saga</code>. Can you show me the pattern that I can use for the future usage of onSnapshots (testable one)?</p>