React Hook recipe from https://usehooks.com

use-auth.jsx

// Top level App component
import React from "react";
import { ProvideAuth } from "./use-auth.js";

function App(props) {
  return (
    <ProvideAuth>
      {/* 
        Route components here, depending on how your app is structured.
        If using Next.js this would be /pages/_app.js
      */}
    </ProvideAuth>
  );
}

// Any component that wants auth state
import React from "react";
import { useAuth } from "./use-auth.js";

function Navbar(props) {
  // Get auth state and re-render anytime it changes
  const auth = useAuth();

  return (
    <NavbarContainer>
      <Logo />
      <Menu>
        <Link to="/about">About</Link>
        <Link to="/contact">Contact</Link>
        {auth.user ? (
          <Fragment>
            <Link to="/account">Account ({auth.user.email})</Link>
            <Button onClick={() => auth.signout()}>Signout</Button>
          </Fragment>
        ) : (
          <Link to="/signin">Signin</Link>
        )}
      </Menu>
    </NavbarContainer>
  );
}

// Hook (use-auth.js)
import React, { useState, useEffect, useContext, createContext } from "react";
import * as firebase from "firebase/app";
import "firebase/auth";

// Add your Firebase credentials
firebase.initializeApp({
  apiKey: "",
  authDomain: "",
  projectId: "",
  appID: ""
});

const authContext = createContext();

// Provider component that wraps your app and makes auth object ...
// ... available to any child component that calls useAuth().
export function ProvideAuth({ children }) {
  const auth = useProvideAuth();
  return <authContext.Provider value={auth}>{children}</authContext.Provider>;
}

// Hook for child components to get the auth object ...
// ... and re-render when it changes.
export const useAuth = () => {
  return useContext(authContext);
};

// Provider hook that creates auth object and handles state
function useProvideAuth() {
  const [user, setUser] = useState(null);
  
  // Wrap any Firebase methods we want to use making sure ...
  // ... to save the user to state.
  const signin = (email, password) => {
    return firebase
      .auth()
      .signInWithEmailAndPassword(email, password)
      .then(response => {
        setUser(response.user);
        return response.user;
      });
  };

  const signup = (email, password) => {
    return firebase
      .auth()
      .createUserWithEmailAndPassword(email, password)
      .then(response => {
        setUser(response.user);
        return response.user;
      });
  };

  const signout = () => {
    return firebase
      .auth()
      .signOut()
      .then(() => {
        setUser(false);
      });
  };

  const sendPasswordResetEmail = email => {
    return firebase
      .auth()
      .sendPasswordResetEmail(email)
      .then(() => {
        return true;
      });
  };

  const confirmPasswordReset = (code, password) => {
    return firebase
      .auth()
      .confirmPasswordReset(code, password)
      .then(() => {
        return true;
      });
  };

  // Subscribe to user on mount
  // Because this sets state in the callback it will cause any ...
  // ... component that utilizes this hook to re-render with the ...
  // ... latest auth object.
  useEffect(() => {
    const unsubscribe = firebase.auth().onAuthStateChanged(user => {
      if (user) {
        setUser(user);
      } else {
        setUser(false);
      }
    });

    // Cleanup subscription on unmount
    return () => unsubscribe();
  }, []);
  
  // Return the user object and auth methods
  return {
    user,
    signin,
    signup,
    signout,
    sendPasswordResetEmail,
    confirmPasswordReset
  };
}

Great Hook! Could make the hook reusable with my changes here (maybe). What do you think?

https://gist.github.com/talves/803d3193b493f28fa34dd867c5aac049/revisions

Thanks! Could you explain how your changes make it more reusable or any other benefits of moving firebase.initializeApp inside useEffect?

When I try to reuse it, I get invalid hook call when using useAuth().

Just fyi, this example will not work in SSR, until Suspense is available in react-dom

@jackguoAtJogg Haven't seen this issue. Is your code online somewhere I could take a look?
@olso By not work do you mean you're seeing an error or just that user will always be null server-side? It's true that this doesn't support getting the user object server-side.

It's working for me! I got it to work.

However, I do ran into a weird issue where the context got cached but im not sure if it has to do with this hook.

@jackguoAtJogg Hmm I wonder if that was maybe Firebase doing something weird. Anyway, let me know if it seems to be a recurring problem.

@gragland useEffect is a no-op on the server

read about it here https://reactjs.org/docs/hooks-reference.html#uselayouteffect

However, there is a solution https://www.npmjs.com/package/@shopify/react-effect

But you will have to add another render ssr pass and await the results

@oslo yeah getting user on server would need to be implemented differently. If using next.js, could be fetched in the getInitialProps method. But I’m also pretty sure firebase stores the token in localStorage, so would also need to grab it and move it into a cookie. Felt like too much complexity to add to this example.

@gragland true, we decided to drop ssr auth state completely due to this for now

@olso yeah I’ve more recently decided that ssr auth just isn’t worth the extra complexity. Maybe it will be much simpler down the road with suspense.

n SSR, until Suspense is available in react-dom

@gragland so you mean that this will NOT work on Next JS?
No wonder I keep getting the auth context undefined

Any child component that needs auth object:
import { useAuth } from "./use-auth.js";
const auth = useAuth()

I keep getting auth is undefined which of course comes from line 56 where we create the context but with no value
const authContext = createContext();
So, what do you recommend (since I'm using NextJS), I'm pulling my hair here (and as you see in my avatar I no longer have hair)?
Any solution will be very appreciated!

@gragland
Well...after thinking a bit more I just deleted the coder related to the Context and kept just pretty much the auth hook component, exported it since that hook returns what I need ( user, signIn, signOut methods, etc) and used it in my sign In page.
Now, do you think that the HandleSubmit looks good?
I'm not sure if I should sync/await the SIGN-IN process and then route to the Account page?!

  const handleSubmit = event => {
    event.preventDefault();

    // TO-DO: dont forget to validate the form

    const signInProcess = async () => {
      const result = await auth.signin(email, password);
      return result;
    };

    signInProcess().then(() => {
      return router.push("/account");
    });
  };

Because the signIn method in the Auth hook example it's a promise based function right?
So should I then async/await on my handleSubmit and then push the Account component?

 const signin = (email, password) => {
    return firebase
      .auth()
      .signInWithEmailAndPassword(email, password)
      .then(response => {
        setUser(response.user);
        return response.user;
      });
  };

Thanks!

@waldothedeveloper the useAuth hook should always return an auth object, as the value is passed in ProvideAuth on line 62. I just tested with Next.js and I'm getting an auth object on server render, as well as client. Do you by chance have your code online somewhere I could check out?

Hey, @gragland I do, check it out here:
link-to-project
Make sure you check the code from the sign_up_page branch NOT the master.

I am having a hard time to also try to protect the route:
/account on SSR with NextJS...any idea how to protect routes on Next JS?

@waldothedeveloper When you originally tested with useProvideAuth and useAuth did you include an _app.js file and wrap all pages with useProvideAuth? For Next.js you'll need to do that so that useAuth can read the context. For example:

import React from "react";
import App from "next/app";
import { ProvideAuth } from "./../util/auth.js";

class MyApp extends App {
  render() {
    const { Component, pageProps } = this.props;

    return (
      <ProvideAuth>
          <Component {...pageProps} />
      </ProvideAuth>
    );
  }
}

export default MyApp;

add:
if (firebase.apps.length === 0) {
firebase.initializeApp(firebaseConfig);
}

should it be setUser(null) instead of setUser(false) ?

When using this snippet, I get the following error in Next.Js

Anyone know what does this mean or how to fix this? My Project is just a skeleton to implement this firebase auth. nothing else.

Nevermind, Its fixed.

I was not using Single Child inside <Link>. So adding <a> fixed it.

Do you need to include setUser(response.user); in all the signin, signup, etc. callbacks or could you just handle it in the onAuthStateChanged callback? It seems to me onAuthStateChanged is called for all of those events anyway?

It would be great to add a note for those who have an infinite loop to use useCallback on api functions : in my app I created an api loader and in the dependency list the linter always asks for my function in it, but when setting the user the function is recreated so is my loader and it creates an infinite loop.

added typescript version
https://gist.github.com/berbaroovez/d6832dc280d2e0b1eca4f862bcf7df09
The User type is from firebase not sure what the import for that is

It would be great to add a note for those who have an infinite loop to use useCallback on api functions : in my app I created an api loader and in the dependency list the linter always asks for my function in it, but when setting the user the function is recreated so is my loader and it creates an infinite loop.

Should the useProvideAuth hook wrap all the provided functions in useCallback? If not… why?