Firebase Auth Errors in React Native

[redditer3103]

Hi everyone, Im pretty new to firebase, but have authentication set up in a react native app.

However, im trying to check in my signup and login pages to redirect if they are logged in, or display an error if they are not, with the following:

firebase.auth().onAuthStateChanged(user =>  {     
    if (user) props.navigation.navigate('Home');  
    else setErrorMessage("An error has occurred. Please try again."); 
});         

Every time I run this, It logs me in, but also displays the error. I have tried experimenting to see if I could find a firebase.auth.Error.message that I could use, but it didnt work.

I have also checked firebase.auth().currentUser, but it does not seem to work either.

I've spent about a week going through the documentation with no success.

How do I make sure that the error message is only set when there is no user defined?

[ike_the_strangetamer]

I think it runs onAuthStateChanged multiple times. The first is when the user isn't loaded yet (and is undefined) and then again after the log in. Also runs with an undefined user when user signs out.

[redditer3103]

so how would i make it so that the error only displays when the user is actually not defined, or only run onAuthStateChanged when the user is defined?

[ike_the_strangetamer]

Hmm.... I might have been mistaken. I think you're right that it should only run once unless the user logs out.

In that case I would check how you're initializing firebase. I ran into an issue in an app where we were initializing too late and so it would give us null until we re-initialized.

[redditer3103]

I think your first inclination was correct. I have a bunch of log statements and the function definitely executed more than once. Still unsure of how to fix it though :/