Neat User and Profile React Hooks for Firebase V9

For a good while, I've been relying on a little package called react-firebase-hooks to turn my Firebase realtime document fetching into tidy hooks. However, this library has become a bit sketchy since the release of Firebase v9 a.k.a the Modular edition.

So, I decided to remove the dependency and write my own little hooks for the two most common types of Firebase objects I use - Users and Profiles (a collection in Firestore).

The useUser Hook

The User hook is pretty straightforward. Firebase already gives us access to a handy function called onAuthStateChanged - an observer for changes to the user's "signed-in" state. It will either return a User object or null, which is perfect for passing straight into a setUser function.

The updateUser function is a bit trickier. I wanted to have a single function that I could pass a displayName, email, password or whatever other properties we could store on a User object. Firebase actually has different update functions for each of these. In the new V9, they're aptly named updateEmail, updatePassword and then updateProfile for everything else (name, photo, etc.)

Combining all this, we get the following hook!

import {
  getAuth,
  onAuthStateChanged,
  signOut,
  updateProfile,
  updateEmail,
  updatePassword,
} from 'firebase/auth';
import { useState } from 'react';
import type { User } from 'firebase/auth';

type UpdateUserProps = {
  displayName?: User['displayName'];
  photoURL?: User['photoURL'];
  email?: User['email'];
  password?: string | null;
};

const useUser = (): {
  user?: User | null;
  updateUser: (props: UpdateUserProps) => Promise<void>;
  logout: () => Promise<void>;
} => {
  const auth = getAuth();
  const [user, setUser] = useState<User | null>(auth.currentUser);

  onAuthStateChanged(auth, setUser);

  const updateUser = async ({
    displayName,
    photoURL,
    email,
    password,
  }: UpdateUserProps) => {
    if (!user) {
      return;
    }

    if (displayName) {
      await updateProfile(user, { displayName });
    }
    if (photoURL) {
      await updateProfile(user, { photoURL });
    }
    if (email) {
      await updateEmail(user, email);
    }
    if (password) {
      await updatePassword(user, password);
    }
  };

  const logout = async () => {
    await signOut(auth);
  };

  return { user, updateUser, logout };
};

export default useUser;

The useProfile Hook

Since Firebase Users can only store high-level account and authentication info such as an email, phone number and photo, it's common practice to create a Profile collection in Firestore that contains any other info you want to store in relation to a particular user. It's also common practice to use the format users/${user.uid} for the collection path, so we'll make sure to accept a User object as a prop.

Anyway, let's talk about fetching data from Firestore. The new V9 has a handy function called onSnapshot that attaches a listener for DocumentSnapshot events, which is a fancy way of saying it subscribes to a collection and listens for updates. That function takes a document reference (or query), a "next" callback (for success) and an "error" callback. It also takes an "onComplete" callback but since the snapshot stream never ends, it's never called, so 🤷‍♀️.

The easiest way to manage all this is to stuff it inside a useEffect function, remembering to cleanup your snapshot at the end (it returns an unsubscribe function 👍). For the dependency array, we want to pass the User's UID so it re-runs every time the user changes (which is handy for clearing the profile data when the user logs out).

Chuck in a loading states, some basic error handling and we've got ourselves a pretty neat profile hook!

import type { User } from 'firebase/auth';
import { getApp } from 'firebase/app';
import { doc, updateDoc, getFirestore, onSnapshot } from 'firebase/firestore';
import type { FirestoreError } from 'firebase/firestore';
import { useEffect, useState } from 'react';

// Whatever your profile looks like!
export type ProfileProps = {};

type UseProfileResponse = {
  profile: ProfileProps | null | undefined;
  updateProfile: (newData: Partial<ProfileProps>) => Promise<void>;
  profileLoading: boolean;
  profileError: FirestoreError | undefined;
};

const useProfile = (
  user: Partial<User> | null | undefined
): UseProfileResponse => {
  const app = getApp();
  const firestore = getFirestore(app);
  const [profile, setProfile] = useState<ProfileProps | null>(null);
  const [profileError, setProfileError] = useState<
    FirestoreError | undefined
  >();
  const [profileLoading, setProfileLoading] = useState(false);

  useEffect(() => {
    if (!user?.uid) {
      setProfile(null);
      return undefined;
    }

    setProfileLoading(true);
    const profileRef = doc(firestore, 'users', user.uid);
    const unsubscribe = onSnapshot(
      profileRef,
      (profileDoc) => {
        setProfile(profileDoc.data() as ProfileProps);
        setProfileLoading(false);
      },
      setProfileError
    );

    return unsubscribe;
  }, [firestore, user?.uid]);

  const updateProfile = async (
    newData: Partial<ProfileProps>
  ): Promise<void> => {
    if (!user?.uid) {
      return;
    }

    const profileRef = doc(firestore, 'users', user.uid);
    await updateDoc(profileRef, newData);
  };

  return {
    profile,
    updateProfile,
    profileLoading,
    profileError,
  };
};

export default useProfile;