feat(login): resetBeforeLogin option to enable/disable resetting of auth and profile on login

[zhang-z]

I call firebase.login({token: token}) every time my app starts, which means login() could be called while the user is already logged in (yup this point can be improved, but the potential issue still exist). In this case, store.firebase.auth got reset to {isLoaded: true, isEmpty: true}. Firebase actions were dispatched in this sequence:

1. AUTHENTICATION_INIT_STARTED
2. AUTHENTICATION_INIT_FINISHED
3. LOGIN -- already logged in, action contains auth: {...}
4. LOGIN_ERROR -- dispatched by login(), see here

I feel the logic of 4th action is not quite right.

To replicate this issue, you can try to run login twice -- 2nd call fired after 1st call finished.

[prescottprue]

LOGIN_ERROR is run with null so that it empties out any login errors that could have occurred from previous login attempts.

For now, it would probably be best to check for auth before you re-run firebase.login.

It seems like we could make a different action that only clears the error, but does not empty the rest of the auth state.

[zhang-z]

Yup, I will add the check in my project.

make a different action that only clears the error, but does not empty the rest of the auth state

This sounds good. Thanks.

[marekolszewski]

There are times when you might want to log the user in a second time. I believe I sometimes do that when Firebase requires a fresh login to change a user's email or password.

[prescottprue]

@marekolszewski In that case, when logging in the second time, wouldn't you want the auth/profile to be removed since it is new data?

[marekolszewski]

@prescottprue Unfortunately, in this case, no. Removing auth redirects the user away from the settings page because they are briefly no longer logged in. Also, the user data doesn't change, though it's true that the auth token will be refreshed and likely different.

I think I solved the issue on my end by using a login popup when someone is accessing a page behind a login wall, but others might still have this issue. I think firebase has a special re-login flow, but I didn't look into it too much. Maybe we can expose that through react-redux-firebase.

[prescottprue]

@marekolszewski and @zhang-z What are your thoughts on a config option (something like emptyBeforeLogin: false) to control this?

In v1 it would have to remain true by default to remain backwards compatible.

I think in v2 it should be false by default, but open to input on that front.

[zhang-z]

resetBeforeLogin sounds a better name over emptyBeforeLogin. Thanks!

[prescottprue]

@zhang-z Glad you saw the new name, was going to mention that. Just to clarify for others, the new config parameter will be resetBeforeLogin.

The update should be released soon, but in the meantime you can try it out on the v2.0.0-beta.8 branch.