react native – What is the error.code of an invalid e-mail, in the case of a user registration in the Firebase?

I am creating a user registration panel in firebase with e-mail and password through an application in React-Native, then, in the act of registration, I wanted to check if the email entered is valid.
AFAIK,

auth / weak-password

it is a small password …
but in the case of an invalid email inserted?