clean-logout.s.md

[Standard] Implementing a clean logout

Owner: Louis Lagrange

Checks

You should remove all persisted and in-memory user content after a logout. You should logout from every external services silently.

• If my project uses react-apollo
  • the cache is cleared with client.resetStore
• If my project uses redux
  • there is a LOGOUT or RESET_CUSTOMER_DATA action that replaces the user reducers' states with the initial states
• If my project uses React-Native AsyncStorage
  • the cache is cleared with AsyncStorage.clear, or AsyncStorage.multiRemove if you need to target only some keys.
• Errors should be caught and handled

Good examples

// pseudo code
const logout = async () => {
  try {
    await fetch('ZENDESK_LOGOUT_URL', { method: 'GET' });
    await firebase.auth().signOut();
    await AsyncStorage.clear();
    ReduxStore.dispatch(resetCustomerData());
    apolloClient.resetStore();
    Navigation.navigate('login');
  } catch (e) {
    HandleErrorService.handleError(e);
    // eventually show an error or retry
  }
}

Bad examples

Example 1

Without cleaning the user data, you will have state and data inconsistencies with the new user.

// pseudo code
const logout = async () => {
  Navigation.navigate('login');
}

Example 2

Without the try catch, the app will crash if the user has no connection, or if another error happens.

// pseudo code
const logout = async () => {
    await fetch('ZENDESK_LOGOUT_URL', { method: 'GET' });
    await firebase.auth().signOut();
    await AsyncStorage.clear();
    ReduxStore.dispatch(resetCustomerData());
    apolloClient.resetStore();
    Navigation.navigate('login');
}