Learn Alpine, Immutable and Testing-library

In 2018, Kent C. Dodds wrote: "The more your tests resemble the way your software is used, the more confidence they can give you." This phrase became the guiding principle for the entire Testing Library ecosystem. 

A few years later, the React Testing Library became the de facto library for writing unit and integration tests in the React ecosystem.

Thanks to its user-centric perspective, our tests are closer to our user experience and far away from implementation details.

In this course, you will learn how to:

- render your components
- properly query your UI for elements while keeping accessibility and your users' experience in mind
- improve your testing experience with the usage of some utilities
- interact with your components to fire events
- leverage asynchronous utilities to customize your testing flow
- get rid of the annoying "not wrapped in act" warning

After this course, you should be able to write and debug any test using the React Testing Library!

The `@testing-library` family of packages helps you test UI components in a user-centric way.

You want to write maintainable tests that give you high confidence that your components are working for your users. As a part of this goal, you want your tests to avoid including implementation details so refactors of your components (changes to implementation but not functionality) don't break your tests and slow you and your team down.

Testing Library accomplish these goals so you can be confident your application will work when it gets to the end user.

testing-library

An Introduction to the React Testing Library

For many years, the most annoying thing about writing tests with the React Testing Library is when the "not wrapped in act(...)" warning appears in your console. act is a React testing util that ensures all UI updates are wrapped up before proceeding with your test case. What we often miss is that we actually don't need act and that this error is there to tell us something instead, and that is: You are not testing everything!

In this lesson, we are going to understand why the "not wrapped in act(...)" shows up and how to get rid of it!

Get Rid of the "not wrapped in act(...)" Warning

Sometimes, you might need to wait for an element to disappear from your UI before proceeding with your test setup or making your assertion.

In this lesson, we will learn about a wrapper around the waitFor that allows you to wait until an element is removed from your UI: the *waitForElementToBeRemoved*.

Use the waitForElementToBeRemoved Async Util to Await Until an Element Disappears

After querying and interacting with elements come assertions. Assertions are really important to assert that your test case really works. Sometimes due to the async nature of your code, your assertion might need to wait some time until it passes.

In this lesson, we will learn how to wait for a period of time until our assertion passes by using the *waitFor* util.

Leverage the waitFor Async Util to Await for an Assertion to Pass

Whilst fireEvent helps to interact with elements, that is not how a user interacts with them. When a user interacts with an element, more than a single event is fired. This means that by using fireEvent, we might be missing some scenarios that might be triggered accidentally by other events.

In this lesson, we are going to learn about the companion library of the React Testing Library that allows you to simulate full interactions with your elements: the *user-event* library.

Simulate All User Interactions With an Element by Using the user-event Library

After querying, the next important part of testing is interacting with our UI. To do this we need to fire events.

In this lesson, we are going to learn how we can fire a single event in our elements by using the *fireEvent*!

Fire a Single Event on an Element Using fireEvent

Querying is difficult! Even if we follow the guiding principles and always start from the queries accessible to everyone, we are bound to get stuck sometimes. To help us out, the Testing Playground was created.

In this lesson, we are going to see how to use the Testing Playground to help us know which query we should use for each element on our UI.

Use the Testing Playground to Help Decide Which Query to Pick

When debugging our tests, one important part is understanding how our UI looks after our component renders or after we apply some changes to it.

In this lesson, we are going to review one util that allows us to print to our console a representation of the DOM tree of our elements: the *debug*

Check to Current Way Your Component Looks Using Debug

In the previous lessons, we always destructured our queries for render. As your test grows and you need more queries, this can become annoying very quickly. 

Ideally, we would have an object that is pre-bound to the document.body and allows us to use all the queries without any need for restructuring.

In this lesson, we are going to see how to tidy our code and save some time by using the *screen* util.

Use the Screen Object to Avoid Query Destructuring From Render

Given how web pages are built nowadays, you might find yourself with multiple instances of the same element.

To avoid querying for a list of elements and then filtering them down, you can constrain your query to a specific area.

In this lesson, we are going to learn how to leverage the *within* helper to constrain our query to a specific element.

Constrain a Query to a Specific Element Using Within

Sometimes, none of the queries above will work for you. Instead of focusing on implementation details, the React Testing Library gives you a controlled way of doing so: using data-testid!

In this lesson, we are going to look at the one query that belongs to the TestId family and should be used as a last resort only: the *byTestId* query.

Get Elements With an Associated Test id Attribute Using the byTestId Query

In this lesson, we will look at one of the queries that are part of the semantic queries family and allow you to find an element by its alt text: the *byAltText* query.



Get Elements With a Matching alt Text Attribute Using the byAltText Query

There will be times when none of the queries accessible to everyone will work out for you. When this time arrives, you can resort to the semantic queries. While these queries make use of HTML5 and ARIa-compliant selectors the user experience when using these attributes varies across assistive technology and browsers.

In this lesson, we will look at one of the queries that are part of the semantic queries family and allow you to find an element by its title attribute: the *byTitle* query.



Get Elements With a Matching Title Attribute Using the byTitle Query

Text is one of the main ways that the users of your page find what they are looking for.

In this lesson, we will look at another one of the queries that are part of the queries accessible to everyone's family and really helpful when finding non-interactive elements: the *byText* query.



Get Elements With a Given Text Match Using the byText Query

Navigating a form with a bunch of elements with filled-in values can be a way to refer to certain elements.

In this lesson, we will look at another one of the queries that are part of the queries accessible to everyone's family and helpful when querying for filled-in form values the *byDisplayValue* query.



Get Elements With a Matching Display Value Using the byDisplayValue Query

Sometimes your form might be missing a label. Whilst they are not a label replacement, placeholders can help give feedback about what that element should be for.

In this lesson, we will look at another one of the queries that are part of the queries accessible to everyone's family and also helpful when dealing with forms: the *byPlaceholderText* query.



Get Elements With a Given Placeholder Text Using the byPlaceholderText Query

When interacting with form fields, the user knows what an element is supposed to do, thanks to its label. 

In this lesson, we will look at another one of the queries that are part of the queries accessible to everyone's family and really helpful when dealing with forms: the *byLabelText* query.



Get Elements Associated With a Label Using the byLabelText Query

Following the guiding principles of the testing library, your tests should resemble how your users interact with your code. This mindset also applies to your queries. Each query can be customized from an accessibility perspective.

In this lesson, we will look at one of the queries that are part of the queries accessible to everyone's family and *the one you should always start with*: the *byRole* query.

The reason why you should always start with this query is that this query allows you to query for elements that are exposed in the accessibility tree and will help you find accessibility issues early on in your code!


Get Elements Exposed in the Accessibility Tree Using the byRole Query

Sometimes you may need to get more than just one result from your queries.

In this lesson, you are going to learn how you can leverage the AllBy variant to extend your queries to find an array of elements instead of a single one.

Use the AllBy variant to get Multiple Instances of an Element

In order for you to interact with the elements in your tests, you need to query for them. Well, sometimes, they take time to show up in your UI.

In this lesson, we will learn about one of the query variants that allows you to search for something that you expect to show up eventually in your UI: the findBy*.


Use the findBy Query to get Elements that Will Show up on the Page

In order for you to interact with the elements in your tests, you need to query for them.

In this lesson, we will learn about one of the query variants that allows you to search for something that you expect not to be in your UI: the queryBy*.


Use the queryBy Query to get Elements that Won't Always be on the Page

When we import assets in React components outside of the `public` folder that Nitro reads for assets by default when running the development server we need to tell Nitro how to find them with the `devProxy` configuration option.

```typescript
export default defineNitroConfig({
  renderer: './renderer.ts',
  devProxy: {
    '/app/assets': 'http://localhost:5173/app/assets'
  }
})
```

This is ultimately inadequate in scenarios where you want to import assets arbitrarily and have them "just work" but works in a pinch.



Use devProxy in Nitro Config to Serve Static Imported Assets in Dev Mode via Vite

Learn how to use devProxy in Nitro Config with Vite to serve static assets in React components in dev mode.

Start with a basic Vite React TypeScript app and enhance it for production use by integrating Nitro as the server. 

This requires a custom Vite plugin for nitro as well as a custom renderer and manually creating Nitro config.

The other way to approach this would be to add Vite to a Nitro app instead. Same basic result.

The [Nitro config reference](https://nitro.unjs.io/config) is a great read of you'd like to explore more options.


Configure a Vite React TypeScript Application on a Basic Nitro Server

Configure a Vite React TypeScript app by integrating Nitro for production, using custom plugins, renderers, and configs.

Quick Get Started style introduction to Vite using `pnpm create vite` with the React TypeScript template.

See [more in the official docs](https://vite.dev/guide/).

Create a Vite App with the React TypeScript Preset

Quick guide to start a Vite app using React TypeScript template with pnpm.

Over the years, your application have grown huge. Sometimes, really HUGE.

Many developers have contributed to the codebase. One day they pushed one coding style, a different one another day. Sometimes even different patterns and solutions for similar problems.

You want to keep your codebase consistent. In the Angular ecosystem, there were well established patterns for doing things the right way ™️. But the old solutions are being challenged by signal-based approach.

Eventually, you ask yourself the key question: **Should you integrate with the NEW solutions or stick to the battle-tested ones, but already considered LEGACY**?

That's a very good question indeed. Don't rush with architectural decisions 🤓.

## 👉 First, think of what problems you want to solve by introducing the change.

Do you have 1k LoC Angular components? Maybe even 2k? Do you and your team enjoy working with these? 😏

Where does the **domain logic and state management code** belong to - do you have a clear guidance on which code should be put where? Have you spot that different devs implement similar features in totally different ways?

Do you keep on asking the same questions over and over again: **whether this certain piece of code** should be **imperative** (plain old object properties and variables) or **reactive** (streams)? It'd be nice to keep all thinga reactive, but more often than not, it introduces complexity.

## 👉 Second, think of long-term consequences.

You are going to have more than one way to **manage the state**. But is that really an issue? If your codebase is modular, separate modules should not depend on each other in any way. Inner abstractions of one should be invisible to the other, etc.

You are going to introduce a **new tool**. On one hand, you need to learn it, and so does your team. But on the other hand, it's a breathe of fresh air. And it's useful to question the way you've been doing things so far. Maybe there's a more effective way?

You are going to embrace signal-based APIs. And that means taking taking advantage of Zoneless Angular. This means using all modern Angular APIs. And you know that signals are the future. Why would you want to stick to the **less performant, less type-safe, less flexible and, objectively, less effective solutions**?

## 👉 Finally, plan your INCREMENTAL integration.

INCREMENTAL is the absolute keyword here. You don't want to tell your PM you need to stop delivering features because of a refactor.

Actually, there's no need for a "refactor". Just pick the first new feature to be implemented. Or pick the one that needs to be extended.

NGRX Signal Store allows you to create both very simple & small stores, as well as bigger ones. **Composition** is the key here.

**Start simple**.

Create a `withState` section with the signals that hold the state. That's already reactive. And relatively simple.

```ts
const initialState: CartState = {
  items: ...,
  rebate: ...,
}

export const CartStore = signalStore(
  withState(initialState)
);
```

Create a `withMethods` section to provide ways to change the state:

```ts
export const CartStore = signalStore(
  ...
  withMethods((store) => ({
    addItem(item: ShoppingItem): void {
      patchState(store, (state) => ({ items: [ ...state.items, item ] }));
    },
    ...
);
```

Create a `withComputed` section to provide all derived computations:

```ts
export const CartStore = signalStore(
  ...
  withComputed(({ items }) => ({
    totalPrice: computed(() => items().reduce(...))
    ...
);
```

**Start simple**.

Now you can (literally) **`inject` this code into your existing solution**. All you need is to inject your brand new NGRX Signal Store implementation into a component, or a service:

```ts
@Injectable()
class ExistingBigService {
  cartStore = inject(CartStore)
  //...  
}
```

and that's it! What's beatiful is that NGRX Signal Store should remain an implementation details (of a component, service, etc). It **shouldn't leak outside to the entire application unintentionally**. Small NGRX Signal Stores help us to **keep logic more modular**.

Don't hesitate - give NGRX Signal Store a try! Start with the [_**Scalable Signals Angular Architecture with NGRX Signal Store**_](https://egghead.io/courses/scalable-signals-angular-architecture-with-ngrx-signal-store-a33abd39) course now!

Integrating NGRX Signal Store with an existing Angular application


Integrate NGRX Signal Store into your Angular app incrementally for modular, reactive state management. Improve consistency and performance with modern APIs.

In React 19, managing script tags efficiently within components can lead to performance enhancements and simpler code structures.

Originally, using script tags directly in a React component involved complex setups, like using `useEffect` to dynamically add JavaScript code. For instance, a component might dynamically inject script tags to load external widgets. This approach, while functional, resulted in multiple script tags and duplicate iframe elements. This duplication not only cluttered the output but also negatively impacted performance by loading scripts multiple times.

The workaround for this would be to manually hoist any common scripts and maybe load them when they weren't needed by any components.

With React 19 we now have a more effective method. This involves directly placing the script tag within the React component's return statement. This approach ensures that React handles the script loading, avoiding the duplication of script tags.

By implementing the script tags this way, the loading initiator becomes React DOM, which efficiently manages script loading and deduplication. This setup prevents multiple requests for the same script when the component is rendered multiple times, enhancing the overall application performance.

Furthermore, directly embedding the script tag simplifies the code, making the component cleaner and more maintainable.

Efficiently Render Script Tags in React 19 Components

Learn how to efficiently render script tags in React 19 components to improve performance by avoiding duplicate script loads and simplifying your code.

Let's learn how to dynamically manage title tags in React 19 applications. Rendering `<title>` dynamically is simple enough, however, a challenge arises when multiple title tags are present in the document, which can lead to issues with screen readers and search engine optimization (SEO). The solution presented involves ensuring that only one title tag is rendered at a time by using conditional rendering.

Also we need to make sure to have a single string within the title tag using a template literal, ensuring our HTML remains valid and optimized.


Deduplicate Title tags with React 19

Learn to manage multiple title tags in React 19 dynamically. Ensure accessibility and SEO by preventing duplicate title tags with clear examples.

In React 19, we can easily add a title tag like "Starship Deets" which then appears in the head section of the HTML even when we render it inside our components. This method also applies to meta tags such as character set and viewport settings, which are also lifted to the head section automatically.

This is an awesome feature because it maintains the same composition style we are familiar with in React components. It simplifies the handling of HTML head elements without needing extra setups like `useEffect` for accessing the head section. Even in situations where our components are rendering within a body element, like within a div, we can manage our head content directly within our components. React takes care of hoisting these elements where they need to go.


Hoist Title and Meta tags in React 19

Hoisting title and meta tags directly in React 19 components allows for simpler composition, similar to other React elements. Manage meta and title tags.

<PodcastLinks />

Dax Raad, known for his strong opinions on Twitter, sat down for a chat about web dev, career moves, and building cool stuff. He's not afraid to throw some heat at popular tools like [Next.js](https://nextjs.org/), though he still helps people use it. Dax is particularly excited about local-first development, which he thinks isn't getting enough attention. He argues that sometimes the best web dev move is to step away from web dev entirely and explore other areas of programming.

When it comes to career growth, Dax encourages developers to think beyond the "web dev" label and see themselves as programmers capable of tackling any challenge. He advocates for trying out weird stuff and learning unusual languages, as these experiences can lead to unexpected opportunities. Taking smart risks in your career can open doors to awesome possibilities.

In the business world, Dax is a fan of making "asymmetric bets" - moves with low downside but huge potential upside. He applies this philosophy to his work on [SST](https://sst.dev/), reasoning that even if it fails, he'll walk away with valuable experience. He also emphasizes the importance of resisting quick payouts in favor of potentially bigger wins down the road.

Looking to the future of tech, Dax is betting on local-first development. He sees potential in getting in early on emerging technologies like [Solid.js](https://www.solidjs.com/). Building in public and making connections in new tech communities can pay off in unexpected ways.

Dax also challenges the notion of constant hyper-productivity in tech. He suggests balancing focused work with time for exploration and learning. Sometimes, he points out, what seems like a "dumb" choice (like learning a niche language) can turn out to be a smart career move in the long run.

## Good Stuff Mentioned

- [Next.js](https://nextjs.org/)
- [Vercel](https://vercel.com/)
- [SST](https://sst.dev/)
- [Elixir](https://elixir-lang.org/)
- [Solid.js](https://www.solidjs.com/)
- [RepliCache](https://replicache.dev/)
- [Linear](https://linear.app/)
- [Remix](https://remix.run/)
- [Shopify](https://www.shopify.com/)
- [React](https://react.dev/)

Developer Career Growth and Asymmetric Bets with Dax Raad

<PodcastLinks />

Dev and Joel discuss React Miami conference, praising its fun atmosphere and location. They chat about React Server Components, with Dev sharing his experience building a mini framework. They talk about Vinxi, Nitro, and the unjs ecosystem as tools for creating custom frameworks. The conversation touches on Vue's popularity outside web dev circles and non-web dev conferences. They discuss the benefits of TypeScript and strongly-typed APIs. Dev mentions his upcoming talk on durable objects at [a conference in Dallas](https://x.com/DThompsonDev/status/1829674506237194456). They end by discussing WebSockets, PartyKit, and platform-specific frameworks.

## What's Good?

- [React Miami Conference](https://www.reactmiami.com/) 
- [Brenley Dueck's blog post on Simple RSC with Vinxi:](https://www.brenelz.com/posts/simple-rsc-with-vinxi/)
- [Vinxi](https://github.com/nksaraf/vinxi)
- [Nitro](https://nitro.unjs.io/guide/configuration)
- [unjs ecosystem](https://unjs.io/)
- [Solid Start](https://start.solidjs.com/)
- [TanStack Router](https://tanstack.com/router/latest) 
- [PartyKit](https://github.com/partykit/partykit) 
- [Durable Objects (Cloudflare)](https://developers.cloudflare.com/durable-objects/)
- [Flightcontrol](https://www.flightcontrol.dev/) 
- [SST](https://sst.dev/)
- [OpenNext](https://open-next.js.org/)

Nitro, Vinxi, and RSCs - What's Good with Dev Agrawal

**Note:** This course is being actively developed and more lessons will be added in the future.

Cursor is an AI-enhnaced code editor that allows you to call upon the robots to refactor or stub out functions for you with natural language. 

In this course, John will show you workflows that will save you time and effort by utilizing the features such as its mult-line editing and context.

In particular, by giving Cursor's AI the proper context, whether that's lines of code or multiple files, you'll get better output when trying to extend or refactor logic that's present.


Bite-size video tutorials for badass web developers.

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