Override HTTP interceptors for GitHub API token requests in testing, handle errors efficiently, export and access the server, and implement cleanup.

Master error case testing in a mock API environment. Verify failure handling, page redirection, and console error capture. Maintain test isolation with cleanup.

Testing Error Handling and Assertions with Mock API Calls

[00:00] We borrowed a lot of stuff from the previous test. This should look kind of familiar. We're gonna make a utility out of this a little bit later. But we want things to behave a little differently now. So instead of sending users off to onboarding, we want them to go to login. So let's add that assertion here so we get our test failing first.

[00:17] So assert redirect, the response should go to login. Now that response is gonna come from this. And I happen to know also that when there's an error, we throw a response object. And so we could do a try catch around this. I don't like doing that. So we're gonna actually just do a catch.

[00:35] And we're gonna take the response and return that response. So that turns that thrown response into just a resolved response. Now we're getting a failure because that response is actually redirecting to onboarding instead of login. And so we want to make sure

[00:51] that that is not happening that way. We also have this assert toast sent. So we wanna have that assertion as well, or that Kelly put together for us. So that is just making sure that our EN toast is gonna be sent. And I should mention also, these assertions are not the best

[01:11] and we will have custom assertions next or a little bit later. So let's assert the toast was sent on that response. And then we also want to make sure that the console error was called as well because we do log an error when that happens. So let's bring in console error.

[01:30] And because we're doing that, we're gonna have to add console error dot mock implementation and that way we don't get the throw from when that happens. So there you go. We've got all of our assertions set up. We're in a good place now. And so now we just need to make sure

[01:49] that we set things up so that this does in fact fail in the way that it's supposed to. So right here, we're gonna say, let's get rid of that as well. We're gonna say server, which is coming from our mocks dot use.

[02:07] And this is an HTTP post that's coming from MSW. And we pass the access token endpoint, which is right here. So we're gonna override that handler for this particular endpoint. And this is gonna take a request. And with that request then, actually we can ignore the request.

[02:31] And in our case, we don't care about the request. We're just gonna send back a failure. And so here we'll say, return new response error status 400. So some kind of error. That's all we're testing is what happens if there's an error. So I save that and we should get a passing test. We do, awesome.

[02:50] So the error case is being taken as a part of this flow. When the access token endpoint returns an error, then we throw the redirect response as we put together in the auth workshop. And then we're handling all of that here.

[03:07] Now, we are making a mess of the world with this server dot use. We need to clean up after ourselves. And so we're gonna add an after each from the test. And this is just going to call server dot reset handlers. And what that will do, we gotta spell it right. There we go.

[03:26] What that's gonna do is ensure that when you start up your server at first here, you provide some handlers. And then all of the handlers you add with server dot use like this are kind of like secondary handlers. They actually will come first. So if they match, then they'll be the ones that are called.

[03:46] And then the existing handlers will get called thereafter if need be. But between these tests, we're going to say, hey, reset the handlers to get rid of those ones that were added with server dot use. And we'll just use the ones that were initialized. So that's what reset handlers is doing for us. And we want that between every test

[04:06] so that we keep our tests isolated. Anytime you mess up the world, you wanna make sure you're thinking about how to clean it up again. That's a lesson for life. So let's talk really quickly about what we did here. First, we updated this to handle the fact that we're throwing a response in this error case. So we catch that.

[04:25] And then we're asserting the redirect went to login because the auth flow failed. The toast is going to be sent to explain what went wrong. We're gonna improve this later. And then we expect the console error should have been called at least once or exactly one time.

[04:44] And then we turned on this mock implementation because if we don't, then our original mock implementation is gonna throw an error and say, hey, you ended up calling console dot error. And here it is actual, let's see. It's gonna be in here somewhere where we're, oh, actually, no, that's failing for another reason altogether anyway.

[05:05] So yeah, you definitely wanna have this mock implementation so we don't log that error. And that takes care of the setup for our test. And then finally, we need to do the pre-setup for the server to make sure that we're overriding

[05:22] the access token HTTP post endpoint so that when the request comes in, we actually make it fail and then we can test the failure case in this case. And then finally, we want to restore the balance in the force. We want to restore things to their natural order

[05:41] having the happy path implemented in our GitHub API mocks. And so we say reset handlers back to the happy path. And that is overriding mocks with MSW.

Testing Error Handling in GitHub API Interceptor

[00:00] The way we've got this written is that any time anybody asks us for any access token, we will gladly create a new GitHub user for them and return an access token. So, it's not exactly the way that the GitHub API actually works, but it works really well for our local development.

[00:18] So, the trick is, we do have logic for what happens if we can't get an access token, if there's some sort of problem there, like maybe GitHub is down, or the code that was provided is invalid, or something like that. And so, we want to test that logic to make sure that never breaks,

[00:35] but our HTTP interceptor handler here is actually not coded in a way that lets us test that. So, we kind of need to override that for this particular test, and there's a way to do that. So, if we come over to our test, you're going to be writing a server.use,

[00:55] which will allow us to override a particular handler for this particular test, so that we can make sure that our logic for handling those errors is correct, and what we would expect what we want it to be. So, this is going to require that we export our server and make it accessible,

[01:14] which is exactly what we are doing right here. So, you need to import this server, and then add a server.use, but we want to make sure we clean up after ourselves as well, and so you're going to be handling that too. So, a couple of things to do on this one. Have a good time.

Discord

Email

GitHub

We all know the drill. The code works on your machine but you didn’t realize the impact of the change you made and it breaks in production. This problem grows exponentially as your application’s size and usefulness grows. Unpredictability can be a developer's worst nightmare.

However, many developers find it difficult to effectively test their code. Manual testing gets tedious fast. Complex logic and async code can be tricky to test effectively.

The Full Stack Testing Workshop will equip you with the tools you need to ensure your app works now and in the future. You'll learn how to write modular, maintainable tests that cover all of your code, from the backend to the frontend.

As the author of the de-facto standard testing library for web development (called eh… Testing Library), I have some solid opinions that have led many teams to much more confidence shipping their code. Let’s get you some of that confidence.

## End-to-End Testing with Playwright

With end-to-end (E2E) testing, you can validate a web app from the user's perspective. This is the closest you can get to a real user interacting with your app. In this section, you'll learn the ins and outs of writing a test with Playwright:

- Best practices for setup before running tests
- Simulating user actions like interacting with the UI to perform a search
- Creating a new user in the database
- Cleaning up after tests have run
- Using playwright fixtures for reliable setup/teardown

## Mocking & Authentication for E2E Tests

When your application relies on external services, you need to have a way to test them without actually using them. Similarly, you don't want to fully onboard a new account every time you test an authenticated user flow. In this section, you'll learn how to re-use the same mocks we’ve been using for development to mock third-party services and simulate logging in:

- Use Mock Service Worker to intercept network requests
- Replace email verification with a local file solution
- Attach cookies to Playwright
- Reusing 2FA logic for local testing
- Testing behavior with different HTTP responses

## Unit Testing

Sometimes you’ve got some really complicated business logic in your app. Business logic that is critical to your application. For this stuff, it’s nice to package it up in its own function or module to keep all that logic in one place. This is the perfect situation where lower level unit testing comes in handy. Here, we'll dive into unit testing with the Vitest framework to ensure that each function and module behaves as expected:

- Organizational best practices
- Asserting outcomes with `expect`
- Recording function calls with spies
- Specifying test behavior with Vitest hooks
- Keeping test output clean to avoid cluttering up the terminal

## Component and Hook Testing

When building React components, you should focus on two users: the user who interacts with a component, and the developer who renders it. By using Testing Library, we can avoid mocking React and its hooks and instead test components as they would be used in a real app:

- Render components with Testing Library
- Simulate the DOM environment on a per-test basis
- Querying for missing elements
- Testing hooks in isolation from React
- Stubbing React context
- Cleanup after testing

## Authenticated Integration

Similar to higher-level E2E tests, it is often necessary to simulate an authenticated user. However, we don't want to test the entire user flow every time we make a change. In this section, you'll learn how to test authenticated operations without the overhead of a full E2E test:

- Generating random session IDs
- Associating sessions with users
- Testing authenticated routes
- Asserting user state in responses

## Custom Assertions

Writing tests is good; writing readable and maintainable tests is better. Custom assertions can make your test code easier to understand and modify. Here you'll learn to encapsulate complex checks into simple, understandable assertions:

- Create matchers for specific states
- Share assertions across tests
- Add custom assertions to TypeScript definitions
- Format test output with colors for readability

## Test Database

There are some decisions to make when writing tests that interact with the database. Testing with the development database has benefits, but requires us to remember to delete data after each test. By using a test database, we can avoid accidents while still being able to run our test suites:

- Set up a test-specific database instance
- Seeding a minimal amount of data
- Defining a global setup for Vitest
- Understanding the importance of module import order

Learn how to write tests that cover all of your backend and frontend code. Web Application Testing covers unit testing, E2E, integration testing, and more!

Web Application Testing

Kent C. Dodds

Developers working on modern web applications today face a myriad of challenges.

The apps we build are expected to be good looking, fast, and secure. They need to be interactive, responsive, and accessible. They need to be SEO-friendly, and they need to be resilient to errors.

In order to be successful, you need to ensure you have a solid foundation to build on.

Full Stack Foundations is a comprehensive, in-depth workshop that sets the stage for the rest of the Epic Web series. It's designed to equip you with the current best practices for handling CSS, routing, data loading, and more.

This isn't some basic "intro" workshop! Even if you're an experienced developer, you'll learn new skills and techniques that will help you build better apps.

<Testimonial author={{name: "Gwen Shapira"}}>

It was 🤯. A lot of fun, and I learned so much in one day. Even with 23 years as a software engineer, I have a much clearer understanding of how the web actually works. Now, months after this workshop, I’m working on a web project and this gave me the mental framework I needed to quickly ramp up and feel competent. I’m not even using the same tools Kent uses in the workshops! 13/10.

</Testimonial>

## Styling

In recent years, CSS has seen a lot of evolution in its usage and tooling. There are new best practices for importing stylesheets, managing assets, and optimizing styles. Failing to follow them can lead to slow-loading pages and a maintenance nightmare.

Here, you'll learn how to handle styling right:

- Loading external stylesheets & other resources
- Managing assets with fingerprinting and caching
- Compilation with PostCSS and Tailwind CSS
- Bundling CSS for libraries and components

## Routing

The URL is critical for the web, and is closely tied to your application's routing. Making suboptimal decisions affects loading performance, navigation, and overall experience.

This section is a deep dive into routing, from the basic filesystem structure through nested routes and dynamic parameters:

- Conventions for signifying routes
- Layout and URL nesting
- Navigation and linking
- Dynamic route params
- Resource routes

## Data Loading

The web is all about data, and nothing frustrates users more than when loading is slow or broken. This section introduces you to AJAX/fetch and Remix loading features, giving you the tools to build stable, fast-loading applications:

- Working with `Request` and `Response` objects
- Fetching data for initial and subsequent loads
- Accessing environment variables
- Connecting routes to loaders

## Mutations

Interactivity makes apps engaging, but also introduces complexity. You need to ensure that the thing that happens when a form is submitted is what the user expects. Here you will use form methods and actions to mutate existing data in a mock database:

- Creating forms with `method` and `action`
- Storing and extracting form data
- Handling invalid submissions
- Form state management
- Specifying intent

*This module sets the stage for the complete Professional Web Forms workshop.*

## Scripting

The browser is capable of quite a lot on its own. Up until this point of the workshop, the Epic Notes application will work without any JavaScript. However, scripting allows us to enhance the user experience in ways that would otherwise be impossible.

In this section, you'll incrementally add in features like client-side pending UI, prefetching, and optimistic updates:

- Scroll position restoration
- Considerations when overriding default browser functionality
- Server and client bundles & entry files
- Preloading data & code for anticipated actions
- Transitions with the `useNavigation` hook

## Search Engine Optimization

Ignoring SEO is like building a store without a sign— people simply won't find you. If you want to be successful, your site needs to be discoverable and optimized for presentation on those platforms.

SEO is a very broad topic, but this section will get you set up on the technical side of the equation:

- Essential tags and attributes
- Overriding default metadata for specific pages
- Dynamically set metadata for social sharing
- Reusing parent data for nested routes

## Error Handling

Even the best apps can break, but what separates the good from the great is how they recover. Lack of proper error handling can lead to frustrated users and lost business.

This section will teach you how to anticipate, handle, and recover from errors, making your application resilient and user-friendly.

- HTTP status codes
- Using `ErrorBoundary` components to contain errors
- Handle thrown errors when fetching data
- Error bubbling from child routes to parent routes
- Implement useful 404 pages

Full Stack Foundations

Forms are the primary mechanism for interactivity on the web.

But for all of their importance, forms can be incredibly frustrating for developers and users alike.

There are a lot of moving parts to consider: 

You need to validate user input and handle complex data structures, while being secure from bots and data-stealing attacks. The UI should inform users of any issues as quickly as possible, and be accessible for all.

The Professional Web Forms Workshop will equip you with the tools to handle all of these challenges and more.

## Form Validation

HTML has several attributes built-in that help with form element validation. Unfortunately, they're not enough on their own. On the client-side, bad actors can bypass checks by manually adding the `novalidate` attribute or making requests directly. On the server side, there's no standard way to respond to validation errors other than a generic 400 status code.

In this section, you'll implement a base level of form validation:

- Essential HTML attributes for validation
- Server-side validation with JSON responses
- Displaying errors with the `useActionData` hook
- Disabling default browser validation messages with `useHydrated`

## Accessibility

Accessibility is often an afterthought, but should be a priority. While forms are just one part of the accessibility equation, they're a big one. In this section, you'll learn how to make sure your forms accessible and usable by all of your application's users:

- Properly associating labels with input fields
- Adding appropriate ARIA attributes when necessary
- Manage keyboard focus in response to errors and user interactions
- Creating and using a `useFocus` hook to direct the user’s focus
- Considerations for accessibility testing

## Schema-Based Validation

Manually writing conditional checks for every field in every form is tedious and error-prone: *Is there content in the field? Is it the right type? Is it within the acceptable range? There must be a better way!*

Fortunately, the combination of the Zod and Conform libraries makes it easy to define reusable declarative schemas to validate form data on the client and server:

- Safely replace HTML validation attributes with schemas
- Zod error handling & message customization
- Progressively enhanced validation with Conform
- Share type-safe validation logic between client and server

## File Uploads

Forms need to support more than just text. Images, videos, audio files, and other documents need a different type of input. Depending on the size of the file, you'll have considerations for how and where it is uploaded. In this section, you'll learn how to handle file uploads in a secure and efficient way:

- Uploading images from an `ImageChooser` component
- Handling file uploads on the server
- Schema validation for file uploads with Zod

## Complex Data Structures

The `FormData` API does not support representing objects or arrays– only key/value pairs. It also won't allow you to nest forms within each other. This makes representing complex data structures difficult without jumping through some hoops. Luckily for us, Conform has a great solution when your forms get complex. Here you'll practice:

- Infer field types with Zod
- Nesting objects as a form
- Represent arrays of fields with the `useFieldList` utility
- Add and remove items with Conform's `intent` buttons

## Spam Prevention with Honeypots

Spam bots are constantly crawling the web, looking for forms to submit junk data to boost their client’s search engine rankings and find holes in your security. This can strain server resources, contaminate databases, and cause other unforeseen consequences. One way to combat this is by using a "honeypot", which will prevent a form from being submitted by a bot. This section will teach you how to:

- Create a simple hidden-field validation
- Add a configurable honeypot instance to an action
- Prevent form submissions that are too fast
- Use environment variables for encryption seeds

## CSRF Protection

Cross-Site Request Forgery (CSRF) attacks are a type of malicious exploit where a user is tricked into performing an action they did not intend to. This is usually done by embedding a link or form in a page that the user is already authenticated to. Think of a user logged into their bank account clicking a link that transfers money from their bank account to the attacker's. To prevent this type of attack, you'll want to:

- Create a signed cookie in the user's browser
- Include unique user tokens in forms
- Validate tokens on the server via request headers

## Rate Limiting

You definitely want to prevent bad actors from making tons of requests to try to brute-force their way into your app or cause general chaos. However, malicious intent and spam aren't the only reasons you need to protect your site. Even too many legitimate requests can cause problems. Rate limiting is a way to prevent users from overloading your server with requests. Here you'll learn:

- Considerations for different limits for `GET` vs. `POST` requests
- Implementing basic rate limiting with Express middleware
- Tiered rate limiting depending on which form is being submitted

Professional Web Forms

Data modeling is as a critical skill for the full stack developer. After all, data is the foundation of your application.

If you don't do it right, you'll find yourself stuck before you even get started. A poorly designed database schema can lead to a lot of headaches down the road when you need to make changes or add new features. Inefficient queries can slow down your application, leading to a poor user experience. Analyzing root causes to issues like these can be a time-consuming and frustrating process.

Web developers spend a ton of time into making their UI handle a slow backend well which is great and you should do that too (you don’t control network latency after all). But *****great***** web developers put effort into making it so their users hardly ever experience that great pending UI by making the backend as fast as possible. Your UI can’t be any faster than your slowest database query.

The Data Modeling Deep Dive Workshop will help you develop a keen understanding of databases and how to manage them. You'll learn the same tools and techniques used at the top tech companies to design robust database architectures and optimize query performance.

We'll be using production grade tools like Prisma and SQLite, but the concepts you learn in this workshop will be applicable to other database systems as well.

## Database Schema

A well-designed database schema is the foundation of your application. It's critical to get it right from the start, as it can be difficult to make changes down the road. This section provides a background on SQL before introducing Prisma's suite of tools. You'll learn:

- SQLite database initialization with Prisma
- Prisma's Object Relational Mapper (ORM)
- Defining a schema with Prisma's declarative schema language
- Converting a schema to SQL with the Prisma CLI
- Viewing and editing your database in Prisma Studio

## Relationships

Poorly planned relationships between database models can lead to data inconsistencies and increased query complexities and performance problems. To avoid these issues, you need to understand the different types of relationships and how to implement them. This section provides you with practical experience in recognizing relationships:

- One-to-many relationships (User has many Notes)
- One-to-one relationships (User has one UserImage)
- Updating the database with Prisma
- Planning models for the future
- Generate an Entity Relationship Diagram (ERD) for visualization

## Migrations

As your application evolves, so will your database schema. It's not uncommon for there to be "breaking changes" that affects one or more of your database models. This is where migrations come in.

Migrations allow you to track and synchronize schema changes across environments. Traditionally migrations have been tricky to manage, but this section will teach you how to use migrations to ensure your development, staging, and production environments are always in sync:

- Generating SQL migration code with Prisma
- Best practices for documenting & tracking migrations
- The "widen then narrow" approach for eliminating downtime
- Experimenting with migrations before permanently applying them

## Seeding Data

Manually adding data to a database is not only time-consuming but also prone to errors. Scripting to the rescue!

Here you'll learn how to populate your databases with consistent data for development and testing purposes:

- Initializing a SQLite database
- Idempotent scripting
- Resetting the database with Prisma
- Nesting SQL queries to simplify foreign key connections

## Generating Seed Data

Using hardcoded seed data works great for small applications, but it won't provide the best idea of how your application will perform at scale. You also shouldn't use real user data during development for plenty of obvious reasons.

A better approach is to use a library like Faker.js. This section will teach you how to use Faker.js to generate seed data for your database:

- Balancing realism with practicality when generating data
- Creating realistic user information
- Varying data quantities and randomness
- Validating against the schema
- Enforce data uniqueness

## Querying Data

In SQL, queries are written with the `SELECT` statement. This is one of the most powerful statements available, but it can also be one of the most complex. This is where tools like Object Relational Mappers (ORMs) come in, helping developers write SQL in a more intuitive way. Although it isn't a traditional ORM, the Prisma Client is an indispensable tool for modern web development. In this section, you'll learn how to get the most out of it:

- Understanding how Prisma's API maps to SQL
- Handling Hot Module Replacement (HMR)
- Logging slow queries
- Pre-connecting the client to the database

## Updating Data

Data mutation is a common task, but doing it incorrectly can lead to data corruption or loss. Especially when a single user action results in multiple database changes (for example, transferring money between user’s bank accounts). Getting mutations wrong can be a serious problem for your app’s success. This section will walk you through techniques for working safely:

- Deleting and updating data
- Conditional upserts
- Combining multiple queries into a transaction
- Rolling back to a previous transaction

## SQL

No matter how great an ORM is, sometimes you have to write raw SQL. In this section, you'll learn how to write raw SQL queries and execute them with Prisma. You'll also practice with:

- Wildcard queries
- Runtime schema validation with Zod
- Using joins to enable more complex queries
- Specifying query result ordering for more efficient searching

## Query Optimization

Nobody likes a slow application.

There are many stories of companies spending millions of dollars on scaling hardware, adding multiple levels of caching, and even rewriting their entire application in pursuit of a faster performance– only to find out later that the solution was optimizing their database indexes and queries.

In this final section, you'll learn how to optimize your queries for maximum performance:

- Identifying the index
- Analyzing raw SQL queries
- Multi-column indexing
- Balancing premature optimization with practicality

Data Modeling Deep Dive

Most web applications feature user accounts in one form or another.

To the user, having a login form seems simple enough. But behind the scenes, there's a lot going on. You need to securely store and manage user sessions, handle authentication and authorization, and protect against malicious attacks.

Without knowledge of the underlying concepts, it's easy to make mistakes (even if you decide to use a third party service or library to do all the hard work for you). Weak authentication systems, misconfigured route protection, and flawed session management all lead to vulnerabilities and negative user experiences.

The Authentication Strategies & Implementation workshop is your guide to implementing industry standard user account flows in a modern web application.

Securely managing passwords, enabling two-factor authentication, and integrating with third-party providers are just some of the processes you will practice. You'll also learn how to handle user preferences, session data, and send emails to users. This will take you all the way to the point where you could easily add Single-Sign On (SSO) support–a must if you’re building a business-to-business application.

There are a lot of moving parts to consider, but this workshop will give you the confidence to tackle them all.

## Cookies

The workshop begins by diving into cookies. This fundamental part of web browsing is often misunderstood, but important to understand. We keep it simple to ramp you up slowly on the web’s original state management solution. This also introduces us to important UI patterns you’ll want to use in other areas of web development as well. It’s surprisingly deep! Topics include:

- Storing user theme preferences in a cookie
- Server-side cookie handling
- Using fetchers for non-navigation mutations
- Optimistic UI updating to apply changes immediately

## Session Storage

Storing user preferences in cookies is fine, but you need to be more careful when it comes to session data. It's vital that users with devtools or malicious client-side JavaScript can't access or modify the data inside of cookies. In this section, you'll learn:

- Cookie-based session data persistence
- Properly getting, setting, and updating session data
- Deleting data after reading
- The flash pattern for short-lived messages

## User Sessions

Depending on the amount of data you need to store, it may make sense to use a different storage mechanism for session data. For this workshop we will continue to use cookies, however we will switch to using a dedicated session cookie. This section will teach you:

- Create a session storage object for storing user data
- Transform form submissions into user objects for storage
- Retrieving user information from cookies then the database

## Passwords

Passwords are the most common way to authenticate that a user is who they say they are. Obviously, storing them in plain text is a bad idea, but even encryption isn't enough. You need to properly prepare to securely handle passwords:

- Create a Password model in the database
- Generate secure password hashes with the battle-tested bcrypt algorithm
- Protection against password attacks
- Update signup route to securely create records

## Login & Logout

At this point, you have the ability to create users and store their passwords. But how do you actually log them in? And how do you log them out? In this one we’re also going to learn about imperative mutations which you’ll definitely want to know for other app features. This section will teach you:

- Verify a user's password hash with bcrypt
- Handling optional vs. required user data
- Guard against timing attacks
- Clearing session data on logout
- Handle edge cases like deleted accounts
- Set expiration dates for session cookies
- Implement automatic logout after a set idle time

## Protecting Routes & Role-Based Access

Most web application have routes that you need to be logged in to access. It's one thing to prevent this in the UI, but the real thing you need to do is protect the data that powers those pages. There are also considerations for different user roles and permissions. This section will teach you how to:

- Ensure users only access data they own
- Restrict private pages to logged in users
- Implement smart redirects for login and logout
- Specify and enforce permissions with Role-Based Access Control (RBAC)

## Managed Sessions

Imagine a user logging in on a public computer, who then forgets to log out. This security risk can be mitigated by implementing a session management feature:

- Add a session model to the database
- Update auth utils, login, and logout routes to query sessions
- Refactor for session expiration support
- Create a page for displaying & managing active sessions

## Email Verification & Password Resets

Email is one of the most common ways to verify a user's identity. If a user loses access to their account, needs to reset their password, or wants to change their email address, you'll need to send them an email. While the actual sending of the email is best handled by a third-party service, the process flow behind the scenes is what you'll need to implement:

- Integrate a third-party email API
- Share session data between routes for multi-step flows
- Style HTML emails
- Generate time-based one time passwords (TOTP) for password resets
- Force verification of email address change

## Two-Factor Authentication

Two-factor authentication (2FA) is a great way to add an extra layer of security to your application. It requires the user to enter a code from a second device along with their username and password. Even if an attacker determines a password, they won't be able to access the account without the second factor. In this section, you'll add 2FA to the Epic Notes application:

- Handle the 2FA enable flow
- Provide the user with a QR code
- Implement a 2FA code input form
- Verify the code and log the user in
- Require re-verification
- Provide option to disable 2FA

## Third-Party Authentication

There are several reasons to use third-party authentication providers. It can be a great way to reduce friction for users, or allow easier access to other data. The most common way to do this is with OAuth 2. Once you’re finished with this section, you’ll be geared up to implement third party auth with any provider. Including Single-Sign On (SSO) flows. We’ll be following these steps:

- Add an authentication strategy to enable GitHub login
- Create a connections model to associate users with providers
- Prevent duplicate account connections & hijack attempts
- Pre-fill user account data based on third-party login
- Mocking third party APIs for testing
- Gracefully handle login errors
- Implement smart redirection to return to original page after login

Authentication Strategies & Implementation

Kent C. Dodds is joined by expert developers, library creators, and tech industry leaders who share their insights and experience working within the ever-evolving world of web development.

These conversations cover a wide range of topics ranging from the intricacies of database efficiency, the future of authorization, the role of leadership in tech, and everything in between.

No matter your level of experience in web development, these conversations offer a wealth of knowledge and ideas that will inspire you to refine your craft, push boundaries, and become an Epic Web dev!

## Content Management Systems with Alexandra Spalato

Alexandra Spalato, a Developer Relations Engineer at Storyblok, discusses the future of content management systems. She emphasizes the significance of a CMS in simplifying complex processes into user-friendly interfaces and making content creation more accessible to non-developers.

## Leadership in Tech with Ankita Kulkarni

Developer and leadership educator Ankita Kulkarni discusses the intersection of leadership and development. The conversation explores the acquisition of leadership skills, and how to find the balance between coding and leadership roles. Ankita provides strategies for advancing into leadership positions, emphasizing the importance of proactive career management.

## API Mocking with Artem Zakharchenko

Artem Zakharchenko, the creator of Mock Service Worker (MSW), joins Kent to discuss the evolution of MSW from a weekend project into to a powerful open-source tool for API mocking and debugging.

## Enhancing SQLite with Ben Johnson

Ben Johnson is a developer with a 20-year coding career spanning roles from Oracle to creating BoltDB. In this conversation, Ben discusses LiteFS and Litestream, both tools aimed at expanding SQLite's utility. Topics include a dive into SQLite's architectural elements, and how LiteFS enhances scalability on a single node.

## The Evolution of Type Safety with Colin McDonnell

Colin McDonnell, a Developer Relations representative at Bun and the creator of Zod, discusses how Zod has grown from its original usage in medical software into a prominent tool in the TypeScript ecosystem. Colin also touches on TRPC, an end-to-end type safety library, and the challenges it addresses.

## Navigating the Testing Terrain with Debbie O'Brien

Debbie O'Brien, a community advocate for Playwright at Microsoft, discusses the adaptability and versatility of Playwright as a testing tool. She emphasizes its value in various testing scenarios and its role in Microsoft's application testing, including VSCode, Bing, and Teams.

## Simplifying Web Form Management with Edmund Hung

Edmund Hung, web developer at Delivery Hero, discusses how Conform has become a crucial component of the Epic Stack. He highlights Conform's unique approach to form management, which bypasses native browser validation in favor of its own system.

## Scalable Databases and Authentication with Iheanyi Ekechukwu

Iheanyi Ekechukwu, a software engineer at PlanetScale, explore database and hosting options, highlights PlanetScale's scalability and the role of Vitess in the technology. The conversation also covers authentication solutions, and cautions against over-reliance on external services.

## Understanding Web Development with Jacob Paris

Jacob Paris joins Kent to discuss his work on Remix. He highlights some of the challenges of server rendering, including handling user preferences and time zones. One the client side, Jacob emphasizes the importance of server output for correct client rendering, especially when users disable JavaScript.

## The Depth of Software Testing with Jessica Sachs

Jessica Sachs, software engineer at Ionic and a testing & QA expert, joins Kent in a conversation about various testing paradigms. They discuss topics ranging from Test-Driven Development to End-to-End testing, emphasizing the importance of a balanced approach.

## Platform Engineering with Jocelyn Harper

Jocelyn "Josie" Harper, tech lead at The New York Times, discusses her tech journey into roles including platform engineering and system design. Additional topics include backend optimization and the significance of documentation.

## Exploring the Front-End Ecosystem with Mark Dalgleish

Mark Dalgleish, co-creator of CSS Modules and contributor at Shopify, discusses the evolution of CSS, React, and design systems. Touching on CSS Modules and CSS-in-JS, the conversation also goes into the challenges of managing design systems, particularly when it comes to balancing flexibility with standardization.

## Navigating Changing Web Technologies with Mark Thompson

Mark Thompson from Google's Angular team joins Kent to share his career journey, the web's evolution, and AI's role in software development. Additional topics include the transformational role of APIs and Angular's transition from the View Engine to Ivy.

## The Magic of TypeScript with Matt Pocock

Matt Pocock, internet-renowned as the "TypeScript guy", discusses the merits and challenges of the TypeScript ecosystem. Highlighting its benefits in IDE capabilities and bug reduction, Matt also touches upon complexities in managing types and creating libraries.

## Building Deep Skills with Michael Chan

Educator and enthusiast Michael Chan shares his thoughts on the changing React landscape, emphasizing the significance of TypeScript and libraries like React Query. He advocates for building a deep understanding over surface-level knowledge. Both Michael and Kent stress the joy of creating meaningful projects and the importance of a comprehensive web development understanding.

## Examining MDX with Monica Powell

Monica Powell, a senior software engineer at Newsela, dives into MDX, which allows for developers to combine JSX with Markdown for creating rich content. She highlights MDX's role in the Unify ecosystem, as well as its challenges when getting started with CMS integration.

## Efficient Form Management with Sandrina Pereira

Sandrina Pereira, a staff front-end engineer at remote.com, emphasizes the significance of web accessibility using the POUR principles. Additional topics include the complexities of managing large-scale forms dynamically for users across the world. 

## Transitioning from Rails to Remix with Sergio Xalambrí

Sergio Xalambrí shares his experience transitioning from a Rails and Next.js setup to Remix at fintech startup Duffy. Some of the challenges include highlighting challenges in internationalization and adding middleware. The conversation also into remix-auth's authentication strategies and contrasting Remix's modular approach with Rails' cohesive framework.

## The Capabilities and Ecosystem of Tailwind CSS with Simon Vrachliotis

Simon Vrachliotis, a Tailwind expert at Thinkmill, praises the benefits and adaptability of Tailwind CSS, emphasizing its alignment with React's component-level concerns. Simon discusses solving for type safety in addition to recommending tools for enhancing the Tailwind workflow.

## The Crucial Role of Database Optimization with Tyler Benfield

Tyler Benfield, a software engineer at Prisma, dives into the intricacies of database efficiency, emphasizing backend optimization for enhanced frontend performance. Tyler also explores the advantages and limitations of ORM tools like Prisma, the potential of SQLite in production, and the universal importance of SQL knowledge across platforms.

## Product Management with Nevi Shah

Nevi Shah, a product manager at Cloudflare, combined her technical and business skills to  transition from academia and consulting into product management. She highlights the role of a product manager in understanding user needs and introduces Cloudflare Pages as a solution for serverless architecture, while also discussing alternative hosting options like Fly.io.

## Remix Behind the Scenes with Ryan Florence

Ryan Florence, co-founder of Remix and React Training, discusses the innovations behind Remix and its transition from React Router. The framework's compatibility with the web's fetch API broadens its server architecture reach, and its recent acquisition by Shopify promises a bright future for Remix.

## From Tech Sales to Engineering with Shaundai Person

Shaundai Person, a senior software engineer at Netflix, joins Kent to discuss transitioning from tech sales to software engineering. She highlights the importance of recognizing and building individual strengths, especially communication, in large corporate settings.

## Art, Code, and Data Visualization with Shirley Wu

Shirley Wu, an award-winning creator specializing in data-driven art, transitioned from the business sector to web development. She shares how her work offers artistic fulfillment and financial stability, but she emphasizes the importance of ethical considerations.

## Understanding the Future of Authentication with Will Johnson

Will Johnson from Auth0 highlights the limitations of password-based authentication and discusses the potential of alternatives like the Web Authentication API (WebAuthn). Will shares his anticipation for a future where biometrics or digital verification replace traditional passwords, as well as a need for more nuanced access controls in growing organizations.


Interviews with Experts

Full Stack Vol 1

Intro to Web Application Testing Workshop

Intro to Web Application Testing 

Intro to End-to-End

Automate tests seamlessly in Playwright UI mode, mirroring manual tester actions. Validate search feature with Playwright's robust tools and intuitive interface

Playwright tests for user interactions, page navigation, search box inputs, and assert URLs, list elements, and items to test web app search functionality.

Writing and Asserting Playwright Tests for Search Functionality

Writing Automated Tests with Playwright UI Mode

Master isolated tests in Playwright and Node for better control, independence, and reliability. Import and run essential APIs for self-sufficient testing.

Create, manipulate URL with search parameters, display user data using encoding. Elevate your app's user data handling skills.

Creating and Interacting with User Data

Isolating Tests for Better Reliability and Flexibility

Clean up test data to maintain test isolation in end-to-end testing. Prevent data buildup in the development database, ensuring smooth, reliable workflows.

Incorporate user deletion in setup and teardown for a pristine testing environment, eliminating unwanted data and ensuring a clean slate for every test.

Proper Setup and Teardown of Testing for Database Cleanup

Test Isolation in End-to-End Testing

Utilize Playwright fixtures to guarantee thorough database cleanup, eradicating test-created user data, bypassing potential pitfalls from alternative methods.

Use Playwright fixtures for custom test objects, properties, behaviors, execute functions strategically, and manage data cleanup efficiently.

Playwright Fixtures for Testing

Implementing Fixtures to Ensure User Deletion in Playwright Tests

Take a break, nourish yourself, hydrate, and jot down your learnings to keep your brain sharp. Let's continue the great work with more testing ahead!

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End-to-End

Address HTTP/S validity with a mock server and stub, this makes it easy to ensure that a client's response is consistent

Intro to E2E Mocking

Capture, save verification codes for smooth server-test automation communication.

Master Node.js email read/write with the File System module. Save, retrieve email data for testing efficiently.

Handling Emails in Node.js using File System

Writing Emails to the File System for Test Automation

Quickly grasp requiring and using disk-stored email data in tests for successful content reading. Crucial for test setup and execution.

Enhance process-to-process communication in Node.js using the secure file system method. Elevate data transfer and parsing capabilities.

Communicating Between Processes with File System in Node.js

Reading Email from Disk in Test Environment

Quickthink about the punning methods you will employ to share skeins of mirth with your fellow yo-cards

Dad Joke Break E2E Mocking

End-to-End Mocking

Learn how to simulate an authenticated user in your tests by generating and adding cookies to the browser context, improving test efficiency and isolation.

Intro to Auth E2E

Master end-to-end user flow tests, streamline authentication, and navigate login, profile editing, 2FA, and login verification.

Simulate user login, set cookies in browser tests to mimic web app authentication accurately.

Login and Setting Cookies for Browser Testing

End-to-End User Flow Testing and Authentication Utility

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Authenticated End-to-End

Intro to Unit Test

Craft solid unit tests for getErrorMessage, covering various scenarios and input-based error messages. Test pure and impure aspects thoroughly.

Master unit testing for utility functions, cover error handling, and achieve full code coverage with tools like coverage reports.

Writing Unit Tests for Utility Functions

Unit Testing a Function for Error Messages

Minimize test output logs, mock console.error for cleaner testing. Master spies for focused, effective testing without excessive console noise.

Utilize spies to track, assert console.error calls in tests. Ensure correct arguments and preserve valuable error info.

Testing Console Error with Spies

Managing Test Output and Error Logging with Console Mocking

Utilize Playwright testing hooks for error restoration and default mock restoration to enhance test stability.

Learn how to restore mocks by default, capture and handle console errors, and create a shared console error setup for efficient JavaScript testing.

Effective Error Handling and Console Capture Testing

Implementing Test Hooks for Error Restoration in Playwright

Create a setup file for automatic inclusion of essential files in all test files, closely simulating the production environment for effective testing.

Set up a test directory with setup files using VTest to automate configuration and common tasks. Ensure smooth test execution and robust error handling.

Setting Up Test Environment and Utilizing Setup Files with VTest

Creating a Setup File for Test Environment Setup

Dad Joke Break Unit Test

Unit Testing

Intro to Component Testing

Efficiently test Error List component rendering with React Testing Library. Gain hands-on experience across diverse test cases.

Simulate DOM with JSDOM for React component testing, skip the browser. Utilize Testing Library, tackle challenges, and hone your skills.

Testing React Components with JSDOM

Error List Component with React Testing Library

Fix test failures from DOM manipulation with proper cleanup techniques for reliable, efficient testing.

Maintain test isolation, eliminate dependencies on test state, and ensure clean execution in Testing Library with effective test cleanup.

Ensuring Isolation and Proper Test Execution

Proper DOM Cleanup for Reliable Testing

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Component Testing

Intro to Hooks

Create a double confirmation feature in React with a custom hook. Explore implementation,testing with RenderHook and Act. Prevent accidental actions effectively

Master custom React hook testing with RenderHook and Act from Testing Library React. Access hook properties through result.current for precise testing.

Testing Custom React Hooks with RenderHook and Act

Double Confirmation Feature

Test hooks with flexibility. Use custom test components or the render hook utility. Tailor your approach to your testing needs and preferences.

Create test components for thorough React hook testing, ensuring API contracts, and validating state changes accurately with Testing Library React and UserEvent

Testing React Hooks

Custom Test Components vs Render Hook Utility

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Hooks

Ensure test-driven development (TDD) by writing testcases from the get-go and developing integration tests quickly in isolation.

Intro to Testing Remix 

Master Remix stubs for isolated component testing, handle edge cases, simulate user states without full end-to-end testing.

Use CreateRemixStub for Remix components with mock data. Test integration with React Testing Library for proper rendering and DOM element waiting.

Rendering Components with Mock Data

Creating a Stub for Testing Component Logic in Remix

Fix a failing test by adding a parent route granting access to root data. Ensure proper rendering and testing of the username route in authenticated settings.

Create authenticated integration tests in Remix by configuring root routes, loaders, and context for precise testing of user interactions.

Creating Routes and Context in Remix

Creating a Parent Route for Accessing Root Data

We interrupt your couch time for this important reminder. Oh, and to keep you feeling healthy and vibrant.

Dad Joke Break Testing Remix 

Testing Remix

Learn how to mock APIs using MSW to enhance testing reliability, handle different scenarios, avoid dependencies, and ensure test isolation.

Intro to Http Mocking

Manually test and modify GitHub sign-in callback in your app. Adjust user association, validate response cookies, and location headers for robust functionality.

Simulate OAuth2 flow, effectively mock GitHub API requests in tests. Ensure robust verification of authentication and API integration in your app.

Testing OAuth2 Flow and Mocking GitHub API Responses

GitHub Sign-In Callback

Learn how to avoid repeating test code by creating reusable functions and avoiding excessive duplication, ensuring efficient and maintainable testing workflows.

Organize code better with bottom setup functions, reduce repetition, and boost readability through parameterization and code sharing.

Efficient Code Organization with Setup Functions

Streamlining Repetitive Test Setup for Optimal Efficiency

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HTTP Mocking

Intro to Auth Integration

Master testing authenticated requests & connections post-login. Simulate sessions, verify for code reliability.

Master user setup, authenticate, and manage connections, including GitHub and DB users, sessions, and test cleanup. Deep dive into authentication.

Creating and Authenticating Users for Connection Setup

Testing Authenticated Requests and Connection Creation

Verify GitHub login session creation with assertions. Cover scenarios like connecting accounts and non-logged-in users.

Extract, check, parse server response's session cookie for user authentication, ensuring DB session creation.

Verifying Session Creation and User Authentication

Assertions for GitHub Login Session Creation

Swap fake data with real user info in routes, use utilities for seamless database user insertion and deletion.

Real DB interactions for user creation/deletion, image addition, request authentication in integration tests. Full UI coverage, no heavy mocking.

Authentication in Database Integration Tests

Integrating Real Database with User Routes

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Authenticated Integration

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Intro to Custom Assertions

Enhance test assertion readability and functionality by creating custom matchers like assertRedirect. Elevate code clarity and error messages.

Elevate your testing game with custom assertions in Jest. Create "to have redirect" and more for precision. Organize in a test util directory for collaboration.

Custom Assertions with Jest's Expect Library

Custom Matchers for Assertions

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Custom Assertions

Extend the Gradle plugin to suit the needs of your projects. Learn about exploring a Cucumber-JVM Gradle boolean condition or approach using

Intro to Test Database

Set a test database with a URL before importing Prisma for seamless client testing. Master import order and setup for success.

Learn how to properly set up an isolated database for testing purposes using Prisma and dynamic imports, ensuring a clean and efficient testing environment.

Setting Up an Isolated Database for Tests

Setting Up a Test Database for Prisma Integration Tests

Learn how to solve conflicts when running tests simultaneously by setting up individual test databases to avoid shared state and data interference.

Learn how to create and manage isolated test databases using unique identifiers, allowing for efficient and independent testing processes.

Isolating Test Databases for Efficient Testing

Managing Test Databases for Parallel Testing

Speed up test execution with a global setup module. Enhance efficiency for faster, full database tests.

Learn how to set up a base database for faster test execution, avoiding repetitive migrations, and utilizing the real database environment efficiently.

Optimizing Test Setup with Global Database Configuration

Optimizing Test Setup

Take a well-deserved break before applying the acquired knowledge to your own projects. Well done!

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Test Database

Discover how to set up and integrate various testing tools, both at the UI and lower levels, to enhance your app's stability and facilitate easier test creation

Get access to Web Application Testing

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