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

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

2. Set up AuthProvider

useAuth uses anAuthProvider 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 ingatsby-browser.js andgatsby-ssr.js. YesuseAuth is built so it doesn't break server-side rendering. ✌️

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

<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:

1. navigate – your navigation function, used for redirects. I've tested with Gatsby, but anything should work
2. auth0_domain – from your Auth0 app
3. auth0_client_id – from your Auth0 app
4. 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 defaultuseAuth's Auth0 client uses these params:

domain andclientID come from your props.

redirectUri is set to use theauth0_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 needopenid for social logins and to be able to fetch user profiles after authentication. Profile and Email too. You can add more via theauth0_params override.

3. Create the callback page

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

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

The goal is to load a page, briefly show some text, and run thehandleAuthentication method fromuseAuth 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 useuseAuth for authentication in your React app.

Here's a login button for example:

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

You can even say hello to your users

CheckisAuthenticated then use the user object. Simple as that.