Learn Auth0, P5 and Zag

An easy to implement, adaptable authentication and authorization platform which basically makes your login box awesome.



auth0

After a user successfully logs in, Auth0 sends an ID token to your React application. Auth0, uses ID Tokens to cache user profile information and give it to a client application. The caching of ID tokens can improve the performance and responsiveness of your React application.

You can use the data from the ID token to personalize the user interface of your application. The Auth0 React SDK decodes the ID token and stores its data in the user object from the `useAuth0()` React hook. 

Customize UI With ID Token Data From The useAuth0 Hook's User Object

React is one of the web’s most popular frameworks for building JavaScript applications. 

If you know what you’re doing, React can drastically simplify how you build, use, and maintain code.

Whether you’re a React newbie or you’re ready for advanced techniques, you can level-up with egghead. Explore our in-depth courses, lessons, and community resources to build more powerful applications and crack open your career.

react

You can log out users from your React application by logging them out of their Auth0 sessions using the `logout()` method from the Auth0 React SDK.

Create a `logout-button.js` file in the src/components/buttons folder

Create a logout button component with the following code

```js
import { useAuth0 } from "@auth0/auth0-react";
import React from "react";

export const LogoutButton = () => {
  const { logout } = useAuth0();

  const handleLogout = () => {
    logout({
      logoutParams: {
        returnTo: window.location.origin,
      },
    });
  };

  return (
    <button className="button__logout" onClick={handleLogout}>
      Log Out
    </button>
  );
};
```

The `logout() method from Auth0 React SDK clears the application session and redirects to the Auth0 /v2/logout endpoint to clear the Auth0 session.

You can pass an object argument to `logout()` to customize the logout behavior of the React application. You can define a `logoutParams` property on that object to define parameters for the /v2/logout call. This process is invisible to the user. 

Pass the `logoutParams.returnTo` option to specify the URL where Auth0 should redirect your users after they log out. 

Setting `logoutParams.returnTo` to `window.location.origin` will ensure that Auth0 redirects your users to your production URL that you add to the "Allowed Logout URLs" list.




End Auth0 User Session with the logout Method from useAuth0 Hook

In this lesson, we create an AuthenticationGuard file that uses the Auth0React SDK to protect React routes by requiring login. 

You need to create the AuthenticationGuard component, pass in a component prop, and use it to protect any React route. 

```js
import { withAuthenticationRequired } from "@auth0/auth0-react";
import React from "react";
import { PageLoader } from "./page-loader";

export const AuthenticationGuard = ({ component }) => {
  const Component = withAuthenticationRequired(component);

  return <Component />;
};
```

Will also demonstrates how to use the AuthenticationGuard component to protect the profile, and admin routes in the application. 

```js
import { useAuth0 } from "@auth0/auth0-react";
import React from "react";
import { Route, Routes } from "react-router-dom";
import { PageLoader } from "./components/page-loader";
import { AuthenticationGuard } from "./components/authentication-guard";
import { AdminPage } from "./pages/admin-page";
import { CallbackPage } from "./pages/callback-page";
import { HomePage } from "./pages/home-page";
import { NotFoundPage } from "./pages/not-found-page";
import { ProfilePage } from "./pages/profile-page";
import { ProtectedPage } from "./pages/protected-page";
import { PublicPage } from "./pages/public-page";

export const App = () => {

  return (
    <Routes>
      <Route path="/" element={<HomePage />} />
      <Route
        path="/profile"
        element={<AuthenticationGuard component={ProfilePage} />}
      />
      <Route path="/public" element={<PublicPage />} />
      <Route
        path="/protected"
        element={<AuthenticationGuard component={ProtectedPage} />}
      />
      <Route
        path="/admin"
        element={<AuthenticationGuard component={AdminPage} />}
      />
      <Route path="/callback" element={<CallbackPage />} />
      <Route path="*" element={<NotFoundPage />} />
    </Routes>
  );
};

```

Use Auth0 component withAuthenticationRequired To Protect React Router 6 Routes

The `isAuthenticated` value represents the authentication state of your users it's tracked by the Auth0 React SDK. This value returns `true` when the user has been authenticated and `false` they're when not. Use `isAuthenticated` to render UI elements conditionally depending on the authentication state of your users.

```js
import { useAuth0 } from "@auth0/auth0-react";
import React from "react";
import { LoginButton } from "../../buttons/login-button";
import { LogoutButton } from "../../buttons/logout-button";
import { SignupButton } from "../../buttons/signup-button";

export const NavBarButtons = () => {
  const { isAuthenticated } = useAuth0();

  return (
    <div className="nav-bar__buttons">
      {!isAuthenticated && (
        <>
          <SignupButton />
          <LoginButton />
        </>
      )}
      {isAuthenticated && (
        <>
          <LogoutButton />
        </>
      )}
    </div>
  );
};
```
Authentication process doesn’t happen in your React application when using Auth0. Your React application will redirect your users to the Auth0 Universal Login page. Auth0 asks for credentials and redirects the user back to your application with the result of the authentication.


Use the Value of isAuthenticated to Render Components Conditionality

Create a `signup-button.js` file under the src/components/buttons folder

Add the following code:

```js
import { useAuth0 } from "@auth0/auth0-react";
import React from "react";

export const SignupButton = () => {
  const { loginWithRedirect } = useAuth0();

  const handleSignUp = async () => {
    await loginWithRedirect({
      appState: {
        returnTo: "/profile",
      },
      authorizationParams: {
        screen_hint: "signup",
      },
    });
  };

  return (
    <button className="button__sign-up" onClick={handleSignUp}>
      Sign Up
    </button>
  );
};
```
Adding `authorizationParams` to the `loginWithRedirect()` configuration object with the `screen_hint ` property and a value of `signup` will take users from your React application to the sign-up page.

Pass authorizationParams to loginWithRedirect to Direct Users to Auth0 Sign Up

Create a buttons folder the src/components folder

Create a `login-button.js` file and add the following code:

```js
import { useAuth0 } from "@auth0/auth0-react";
import React from "react";

export const LoginButton = () => {
  const { loginWithRedirect } = useAuth0();

  const handleLogin = async () => {
    await loginWithRedirect({
      appState: {
        returnTo: "/profile",
      },
    });
  };

  return (
    <button className="button__login" onClick={handleLogin}>
      Log In
    </button>
  );
};
```

`loginWithRedirect()` redirects to the Auth0 /authorize endpoint to start the authentication process. You can pass a configuration object to this method to customize the login experience.

Setting up the value of `appState.returnTo` to "/profile", you are telling the Auth0 React SDK to: When my users log in with Auth0 and return to my React application, take them to the "Profile" page.

If you don't set up this `appState.returnTo` option, your users will be redirected by default to the / path after they log in.

Apply useAuth0 hook and loginWithReditect to Add User Login to React Application

Install the Auth React SDK on the terminal 

```bash
npm install @auth0/auth0-react
```

Create an `auth0-provider-with-navigate.js` file in the src folder.

Add the following code.

```js
import { Auth0Provider } from "@auth0/auth0-react";
import React from "react";
import { useNavigate } from "react-router-dom";

export const Auth0ProviderWithNavigate = ({ children }) => {
  const navigate = useNavigate();

  const domain = process.env.REACT_APP_AUTH0_DOMAIN;
  const clientId = process.env.REACT_APP_AUTH0_CLIENT_ID;
  const redirectUri = process.env.REACT_APP_AUTH0_CALLBACK_URL;

  const onRedirectCallback = (appState) => {
    navigate(appState?.returnTo || window.location.pathname);
  };

  if (!(domain && clientId && redirectUri)) {
    return null;
  }

  return (
    <Auth0Provider
      domain={domain}
      clientId={clientId}
      authorizationParams={{
        redirect_uri: redirectUri,
      }}
      onRedirectCallback={onRedirectCallback}
    >
      {children}
    </Auth0Provider>
  );
};
```

Wrap the `Auth0ProviderWithNavigate` component around the `App` component inside of `index.js` to give it access to the `Auth0Context`.

`Auth0ProviderWithNavigate` needs the `BrowserRouter` component from React Router to be its parent, grandparent, or great-great-great-grandparent.


Install Auth0 React SDK and Create Auth0Provider with Access to Session History

Click the **Create Application** button.

Sign up for a [free Auth0 account](https://a0.to/egghead-react) here. 

Add the name "React Code Sample" and select "Single Page Applications" and the application type then click **Create**

Click on the **Settings** tab of your Auth0 Application page, scroll down to "Application URIs" section, and fill in these values:

**Allowed Callback URLs**
http://localhost:4040/

**Allowed Logout URLs**
http://localhost:4040

**Allowed Web Origins**
http://localhost:4040

Scroll down and click the **Save Changes** button.

On the "Basic Information" section get the Auth0 Domain and Auth0 Client ID values and paste them a `.env` file in the root of the project.

```env
REACT_APP_AUTH0_DOMAIN=AUTH0-DOMAIN
REACT_APP_AUTH0_CLIENT_ID=AUTH0-CLIENT-ID
REACT_APP_AUTH0_CALLBACK_URL=http://localhost:4040/
```





Link Auth0 Application to React Application

Start by cloning the `spa_react_javascript_hello-world_react-router-6` repository on its starter branch:

```bash
git clone -b starter git@github.com:auth0-developer-hub/spa_react_javascript_hello-world.git
```

Change your current directory to `spa_react_javascript_hello-world_react-router-6`

```bash
cd spa_react_javascript_hello-world
```

Install the project dependencies

```bash
npm install
```

Run the React application on `http://localhost:4040`

```bash
npm start
```


Download Starter Application from Auth0 Developer Center

Learn how to build a pin-input component with state machines, Zag.js and React.

We’ll look at modeling a UI component with state machines, implementing those in a framework agnostic way using Zag.js, and connect the logic to the UI component.

This course is a must-watch if you’re unfamiliar with State machines, and want to learn how to use them to build UI components with ease.

In this course, you will:

- Learn fundamental concept of state machine, event and transition
- Model a UI component with state machine
- Connect state machine logic to UI
- Manage DOM events in state machines
- Create custom React hooks with state machines

A collection of framework-agnostic UI component patterns like accordion, menu, and dialog that can be used to build design systems for React, Vue and Solid.js

Statechart Driven UI Components with Zag.js

In many projects, it is useful to separate the logic that you right with the view that you create so that you can easily share that logic throughout your application. In React we do this with custom React hooks.

We'll improve on the reusability of the pin input component by refactoring it to a custom React hook. To do this we will utilize the prop getter pattern 

This Headless Component pattern is a very useful pattern when building reusable components. It allows you separate functionality from presentation, making it easy to style them as needed.


Refactor Zag.js State Machine Powered Pin Component Functionality to a Custom React Hook

In some cases you'll want to actually have your pin input in a form to handle submitting the values. What's awesome about our implementation is that it doesn't get in the way of adding functionality like this.

First we'll extend our state machine to focus the first input when we click on the input label. Then we'll wrap our Pin Input component in a form element and implement an onSubmit. We can submit values of the form by creating a hidden input and set it's values to the joined values of the other inputs.


Submit Pin Input Values in a Form with a Hidden Input

When the pin input values are full we will want to do something with those values such as sending an HTTP request.

To do this we'll implement a callback in context that will get invoked when all the values are computed. We'll do this by creating a computed property that returns true when all values in context are full. From there we will watch that computed property to invoke our callback.

Trigger Side Effects using Zag.js computed and watch Properties

We have a bug in our pin input. Only 1 value should be allowed per input but if we focus an input that already has a value we can still input another value. 

Let's fix that.

We'll need to implement a function `getNextValue` that will take in the focused value of the current input and the event input that is coming in. After a set of conditionals we will select the value that wasn't the current focused value to update the field.


Implement Conditional Logic in a Zag.js Action to Enforce a Single Character Per Input

The paste event is a unique input event that we need to handle. When we paste a value in from the clipboard, we need to split that value and input single characters to the individual inputs in our Pin Input.

To do this we will need to `preventDefault` in the `onPaste` event so that we can implement our custom logic here. Next we'll implement `setPastedValue` that splits and iterates over the input value we receive and sets it into context. 

Finally we'll implement `focusLastEmptyInput` that looks up the index of the first empty value with `findIndex` and focuses that index.


Spread Values Across a Pin Input Field in a Zag.js State Machine 

We'll be implementing the backspace event which triggers two actions: `clearFocusedValue`, and `focusPreviousInput`. 

These implementations you'll be familiar with at this point but what you'll notice when we actually try to hit backspace that the focus value will get cleared but we won't be setting focus to the previous input. This is because there are several DOM mutations happening at the same time. We'll fix this by scheduling the focus of inputs to the next animation frame with `requestAnimationFrame`


Schedule Input Focus with requestAnimationFrame to Handle Multiple DOM Mutations in Zag.js

Let's actually implement inputting values into our Pin input. We have 3 functions that need implemented. They are `setFocusedValue`, `focusNextInput`, and `executeFocus`. The first two will be pretty straight forward in grabbing values from context and our events and setting new values to our context. 

When we finish implementing `setFocusedValue` and `setFocusedInput` we'll need a way to actually trigger our focus to be set in the DOM. This is where the watch property in a Zag.js State Machine comes into play. We will watch the `focusedIndex` context value and run `executeFocus` any time the focus index changes in our machine (e.g. when `focusNextInput` is triggered after an input event).


Trigger Side Effects in a Zag.js State Machine with the watch Property

Now that we have a machine and our UI is sending it events, we need to actually do something with events that are sent. This is where actions come into play.

We'll implement focus and blur events for the input by setting the context `focusedIndex` to the index that is coming in from the UI. We can mutate context directly in Zag.js because it handles mutations through proxies to stay reactive.


Implement a State Machine Action for Setting Input Focus in Zag.js

Now that we have a machine defined we need to send it events with the relevant data from the UI. To do this we'll need to install the useMachine hook from `@zag-js/react`. From there we'll wire up the actions that we need to send on the input element (e.g. onChange, onFocus, onBlur, and onKeyDown).

Connect Zag.js Machine Logic to React UI through the useMachine Hook

TypeScript is a typed superset of JavaScript that compiles to plain JavaScript.

typescript

We've mapped out what a Pin input state machine should look like so now it's time to start implementing that in code. 

We'll be using Zag.js to model the machine for us. Zag.js works well with TypeScript so the first thing to do is create types for the machine context and state. Then we'll stub out the states, transitions, and actions for the machine. 

While we aren't implementing the actions in this lesson you'll quickly see how a state machine makes complex interactions easier to understand by the events that occur and the actions that are triggered by those events.

Lastly, we'll paste our machine in the stately machine visualizer and you'll see a visual representation of the machine that was created.


Create and Visualize a Pin Input State Machine with TypeScript and Zag.js

We’ll spin up a Vite project for React and install the required Zag.js dependency to model the pin input component logic.

Set up a React + Zag.js Project with Vite

Creating powerful and context-aware tools for Cursor IDE becomes straightforward when leveraging information directly from your current project. In this lesson, you'll learn how to build a custom MCP (model context protocol) tool that intelligently requests essential details—such as the current project path and conversation summaries—from your Cursor project.

Workflow demonstrated in this lesson:

- Define MCP tool parameters to request specific project details.
- Pass project path and conversation summaries into your MCP tool.
- Automatically write or update files within your current project using these parameters.

Key benefits:

- Automate tasks with precision based on your active project's context.
- Simplify interactions by creating AI-driven CLI commands tailored to your needs.
- Open endless possibilities for integrating external APIs and advanced automation.

Through this practical demonstration, you'll gain a versatile technique for enhancing your development workflow in Cursor IDE.

[https://github.com/johnlindquist/mcp-cursor-tool-starter](https://github.com/johnlindquist/mcp-cursor-tool-starter)

John Lindquist

Build MCP Tools Using Project Context for Custom Cursor IDE Automation

Setting up custom MCP (Machine Command Protocol) servers in Cursor can involve tedious steps, such as configuring node paths or referencing additional commands. This lesson shows how to streamline this process by bundling your MCP server directly into a standalone executable.

Workflow demonstrated in this lesson:

- Use a simple MCP server project starter.
- Run a single bundling command to create an executable.
- Right-click the generated executable, copy its full path, and add that directly to your Cursor settings.

Key benefits:

- Eliminates the need for complex node path configurations.
- Simplifies the setup and integration of custom MCP servers into Cursor.
- Makes the server executable instantly accessible within your Cursor environment.

By following this streamlined approach, you can quickly and easily integrate custom MCP servers into Cursor, making your development workflow cleaner and more efficient.

[https://github.com/johnlindquist/mcp-cursor-tool-starter]()

Easy MCP Server Setup in Cursor IDE with Bundled Executables

TanStack Router is the foundation for TanStack Start, which is gaining significant attention due to its innovative approach to application development.

This course focuses on getting effective TanStack Router, a modern and scalable routing solution for React applications. You will learn how to:
- set up and scaffold new applications,
- use file-based routing
- create nested routes
- manage dynamic route parameters and more.

The course covers advanced features like route loaders, caching strategies, and lifecycle hooks, which are crucial for enhancing application performance and user experience.

By understanding TanStack Router, you can build more efficient, type-safe, and maintainable applications, leveraging its integration with data fetching libraries like TanStack Query.

This knowledge is essential for developers looking to improve their routing skills and stay ahead in the field.

Tomasz Ducin

Up and Running with Tanstack Router and React

Learn TanStack Router for React: set up apps, use file-based routing, manage routes, and boost app performance.


In this lesson, we explore how TanStack Router integrates with the [native browser history API](https://developer.mozilla.org/en-US/docs/Web/API/History) to manage navigation.

As we navigate through different routes, the URL changes are stored in the browser's history, allowing users to use the forward and backward buttons to traverse their navigation history.

This functionality also **enables permalinks**, meaning users can copy and paste URLs to access specific routes directly.

Additionally, we learn how to programmatically interact with the history object to move forward or backward through the navigation stack, enhancing the user experience by providing full control over navigation actions.

This compatibility with the native history API ensures that TanStack Router applications behave similarly to traditional websites, offering a seamless and intuitive user experience.

Browse History in Tanstack Router

Browse history in TanStack React Router using the native history API for seamless navigation

In this lesson, we explore how to hook into TanStack Router's lifecycle hooks to execute custom logic during route changes.

The hooks we'll look into are: `onEnter`, `onStay`, and `onLeave`, which are triggered when entering, staying within, or leaving a route, respectively.

All hooks receive a detailed match parameter, providing information about the route's path, ID, and tons of other details.

This allows for the implementation of features like animations or logging when navigating between routes.

We also learn how to use these hooks to track and manage state changes as users interact with the application, making it easier to implement complex behaviors based on route transitions.

Hook into Route Lifecycle Hooks in Tanstack Router

Hook into TanStack React Router's lifecycle hooks for custom route logic and animations.

In this lesson, we learn how to handle not found errors in TanStack Router by using the `notFoundComponent` at both nested and global levels.

To trigger the display of a `notFoundComponent`, we must throw a specific error using the `notFound` function within a loader or other lifecycle method of a route. This approach allows us to provide custom error messages for specific routes or globally across the application.

We explore how to define a notFoundComponent within a specific route's configuration and how to set a `defaultNotFoundComponent` at the router global level, which applies to all routes unless overridden locally. This flexibility ensures that users receive meaningful feedback when encountering non-existent routes.

Provide NotFoundComponent at Nested Route or Global Level in Tanstack Router

Handle notFound errors in TanStack Router with notFoundComponent at nested or global levels.



In this lesson, we learn how to access dynamic route parameters using the `useParams` hook in TanStack Router.

When used with a specific `Route` object, `useParams` provides type-safe access to route parameters, ensuring that TypeScript knows the exact types of these parameters.

This approach eliminates the possibility of undefined/optional values, making it safer for accessing parameters like `employeeId`.

However, when using `useParams` globally without specifying a route, it requires an options object with `{ strict: false }`, which reduces type safety.

In this case, the hook can access parameters from any route in the application, but it does not guarantee their existence or type. This flexibility allows components to be reused across different routes, but it requires careful handling of potential errors.



Access Dynamic Route Parameters with useParams in Tanstack Router

Access dynamic route parameters with useParams in TanStack React Router for type-safe routing.

In this lesson, we learn how to reorganize file-based routes in TanStack Router to accommodate nested routing structures.

We explore how to create additional nested routes by converting files into directories, allowing for further nesting.

For example, to create a nested route like `/employees/$employeeId/edit`, we can create a **directory** (!) named `$employeeId` and place an `index.tsx` file inside it to define the route component for this nested route.

This approach provides flexibility in organizing files while maintaining the convention that file names and locations align with route paths. We also see how to adapt existing components and loaders to work with these reorganized routes, enabling features like edit forms or delete actions (or whatever) within nested routes.


Reorganize File-Based Routes in Tanstack Router

Reorganize file-based routes in TanStack Router for flexible nested routing.



In this lesson, we learn how to parametrize the loader for a nested route in TanStack Router.

We focus on a nested route like `/employees/$employeeId`, where the `$employeeId` is a **dynamic parameter**.

To fetch data for this route, we use a `loader` function that accesses the `$employeeId` parameter. This is achieved by using the params object available in the `loader` function, which contains the dynamic segments of the URL. We then use this parameter to call a function like `getEmployeeById`, which fetches specific employee details from an API.

We highlights that TanStack Router **automatically infers types** for these parameters, ensuring type safety for nested routes.

Parametrize Route Loader for Nested Route in Tanstack Router

Parametrize nested route loaders in TanStack Router using path parameters

In this lesson, we learn how to create nested routes and outlets in TanStack Router using file-based routing.

We start by creating a new `employees` directory and files to represent nested routes, such as `/employees/$employeeId`. The `$` symbol is used to denote dynamic parameters.

We then use the `<Link>` component from TanStack Router to create links to these nested routes, passing necessary parameters.

To render the nested content, we use the `<Outlet>` component (nested), which automatically renders child routes. This approach allows us to dynamically display stuff under a nested route.

All the time, the TanStack Router generator automatically updates the route tree based on file changes - our routing configuration remains consistent 🔥



Create Nested Route and Nested Outlets in Tanstack Router

Create nested routes and outlets in TanStack Router using file-based routing

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