useAuth – the simplest way to add authentication to your React app

The simplest way to add authentication to your React app. Handles everything for you. Users, login forms, redirects, sharing state between components. Everything

How to use useAuth

useAuth is designed to be quick to setup. You'll need an Auth0 account with an app domain and client id.

1. Install the hook

$ yarn add react-use-auth

Downloads from npm, adds to your package.json, etc. You can use npm as well.

2. Set up AuthProvider

useAuth uses an AuthProvider component to configure the Auth0 client and share state between components. It's using React context with a reducer behind the scenes, but that's an implementation detail.

I recommend adding this around your root component. In Gatsby that's done in gatsby-browser.js and gatsby-ssr.js. Yes useAuth is built so it doesn't break server-side rendering. ✌️

But of course server-side "you" will always be logged out.

// gatsby-browser.js

import React from "react"
import { navigate } from "gatsby"

import { AuthProvider } from "react-use-auth"

export const wrapRootElement = ({ element }) => (
	<AuthProvider
	  navigate={navigate}
	  auth0_domain="useauth.auth0.com"
	  auth0_client_id="GjWNFNOHq1ino7lQNJBwEywa1aYtbIzh"
	>
	  {element}
	</AuthProvider>
)

<AuthProvider> creates a context, sets up a state reducer, initializes an Auth0 client and so on. Everything you need for authentication to work in your whole app :)

The API takes a couple config options:

navigate – your navigation function, used for redirects. I've tested with Gatsby, but anything should work
auth0_domain – from your Auth0 app
auth0_client_id – from your Auth0 app
auth0_params – an object that lets you overwrite any of the default Auth0 client parameters

PS: even though Auth doesn't do anything server-side, useAuth will throw errors during build, if its context doesn't exist

Default Auth0 params

By default useAuth's Auth0 client uses these params:

const params = {
    domain: auth0_domain,
    clientID: auth0_client_id,
    redirectUri: `${callback_domain}/auth0_callback`,
    audience: `https://${auth0_domain}/api/v2/`,
    responseType: "token id_token",
    scope: "openid profile email"
};

domain and clientID come from your props.

redirectUri is set to use the auth0_callback page on the current domain. Auth0 redirects here after users login so you can set cookies and stuff. useAuth will handle this for you ✌️

audience is set to use api/v2. I know this is necessary but honestly have been copypasting it through several of my projects.

responseType same here. I copy paste this from old projects so I figured it's a good default.

scope you need openid for social logins and to be able to fetch user profiles after authentication. Profile and Email too. You can add more via the auth0_params override.

3. Create the callback page

Auth0 and most other authentication providers use OAuth. That requires redirecting your user to their login form. After login, the provider redirects the user back to your app.

Any way of creating React pages should work, here's what I use for Gatsby.

// src/pages/auth0_callback

import React, { useEffect } from "react"

import { useAuth } from "react-use-auth"
import Layout from "../components/layout"

const Auth0CallbackPage = () => {
  const { handleAuthentication } = useAuth()
  useEffect(() => {
    handleAuthentication()
  }, [])

  return (
    <Layout>
      <h1>
        This is the auth callback page, you should be redirected immediately.
      </h1>
    </Layout>
  )
}

export default Auth0CallbackPage

The goal is to load a page, briefly show some text, and run the handleAuthentication method from useAuth on page load.

That method will create a cookie in local storage with your user's information and redirect back to homepage. Redirecting to other post-login pages currently isn't supported but is a good idea now that I thought of it 🤔

PS: Make sure you add <domain>/auth0_callback as a valid callback URL in your Auth0 config

4. Enjoy useAuth

You're ready to use useAuth for authentication in your React app.

Here's a login button for example:

// src/pages/index.js

const Login = () => {
  const { isAuthenticated, login, logout } = useAuth()

  if (isAuthenticated()) {
    return <Button onClick={logout}>Logout</Button>
  } else {
    return <Button onClick={login}>Login</Button>
  }
}

isAuthenticated is a method that checks if the user's cookie is still valid. login and logout trigger their respective actions.

You can even say hello to your users

// src/pages/index.js

const IndexPage = () => {
  const { isAuthenticated, user } = useAuth()

  return (
    <Layout>
      <SEO title="Home" />
      <h1>Hi {isAuthenticated() ? user.name : "people"}</h1>

Check isAuthenticated then use the user object. Simple as that.

Checklist for configuring Auth0

There's a couple of required configurations you need to make in Auth0 to make useAuth run smoothly.

Callback URLs

You need to allow both local development and your production app in callback URLs. It's a whitelist that tells Auth0 that your login request is coming from the right source.

Allowed Web Origins

useAuth avoids using local storage for secure tokens. For Auth0 to know that our checkSession request is coming from the right source, you need to add your URLs to allowed web origins.