Firebase warning about fyi

[hsubox76]

Hi, I'm a maintainer of the Firebase JS SDK and just wanted to add some info and apologize for so many rapid changes.

The docs on that Expo page are correct for v9, and in v10.0.0 we switched to automatically providing AsyncStorage for the convenience of React Native users, but this turned out to cause a number of problems for non-React-Native users so we had to roll it back to asking React Native users to explicitly provide AsyncStorage when initializing Firebase Auth, which happened in v10.3.0, release yesterday. The new syntax (correctly described in that warning message) is somewhat different from the 9.x.x syntax as there is no default AsyncStorage to fall back to (it used to be the one bundled in the "react-native" module itself, which is removed now) and the user must always explicitly import and provide it.

[amandeepmittal]

Thank you @hsubox76 for providing the info about the latest changes! Appreciate your effort and work with the Firebase JS SDK library.

Also, thank you @iM-GeeKy for bringing this to our attention. We'll update the FYI guide soon.