Learn Javascript, Netlify and Svelte

JavaScript® (often shortened to JS) is a lightweight, interpreted, object-oriented language with first-class functions, most known as the scripting language for Web pages, but used in many non-browser environments as well such as node.js or Apache CouchDB. It is a prototype-based, multi-paradigm scripting language that is dynamic, and supports object-oriented, imperative, and functional programming styles.

javascript

The new [cause](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/cause) data property that you can add to a thrown `Error` can be used to retain access to the original error caught in a promise rejection. 

Improve Application-wide Error Handling rethrowing JavaScript Error with the Error Cause

You can finally make your numbers more readable in JavaScript. Add underscores in all types of numbers including BigInt, floats, hexes, octals, and binary to improve their readability. 

Just don't add the underscores to the beginning or end!

Make JavaScript Numbers more readable using Numeric Separators

[Promise.any](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/any) takes an iterable of promises and returns a promise that fulfills with the first promise that fulfills, and rejects when ALL of the promises in the iterable reject. 

[Promise.allSettled](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/allSettled) takes an iterable of promises, and returns an array of objects. The objects have a `status` property which is a string that is either `"fulfilled"` or `"rejected"`. If the `status` is `"fulfilled"` the object will contain a `value` property with the resolved value of the promise, and if the `status` is `"rejected"` the object will have a `reason` property with the reason for the promise's rejection. 

Manage Asynchronous JavaScript code with any, allSettled new Promise Methods

If we want to be able to modify the state of a promise from outside the constructor, we can use the [Promise.withResolvers](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/withResolvers) method to get access to the promise, and its `resolve` and `reject ` functions. 



Manually settle a promise using Promise.withResolvers

The [Logical Assignment Operators](https://github.com/tc39/proposal-logical-assignment) bring syntactic sugar over verbose syntax which enforced us to write explicit `if` statements. Thanks to the new operators `||=`, `&&=` and `??=` we can express the conditional logic in a more concise way.

Simplify JavaScript code with Logical, Assignment and Optional Operators

The new [Array.with](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/with) method gives you an immutable syntax for changing values of an array at a specified index. 

Sometimes `.map` will be more efficient. So, in this lesson we'll compare both methods while replacing an object at a specific index.


Simplify array immutable changes with the new array.with method

You no longer need to write generator functions to create basic lazy iterator functions.

Now, ECMAScript supports iterator helpers that you can call on `Array.values()`. With these helpers, the values of an array will be operated on lazily, and will only run when the values are needed.



Make JavaScript computations lazy using Iterator Helpers

The ["Set Methods"](https://github.com/tc39/proposal-set-methods) proposal introduces 7 new methods to JavaScript/ECMAScript:
- `union`
- `intersection`,
- `difference`,
- `symmetricDifference`,
- `isSubsetOf`
- `isSupersetOf`
- `isDisjointFrom`

Thanks to them, complex operations using JavaScript sets will become much easier.

Perform Set Operations using JavaScript Set Methods

Finding elements starting from the end of an array has gotten a lot easier with the introduction of the `at`, `findLast`, and `findLastIndex` methods!

With `at` you no longer need to remember to access the end of the array like `array[array.length - 1]` trick. You can just call `.at[-1]` to get the last element!

`findLast` and `findLastIndex` work the same as their `find` and `findIndex` counterparts. But, they work backwards from the end of the array. This is useful if you know what you're accessing is going to be closer to the end.

Find Items from the end of the JavaScript Array using at, findLast and findLastIndex

[Array Grouping](https://github.com/tc39/proposal-array-grouping) is the new feature of JavaScript/ECMAScript, which splits an array (or, generally, an iterable), into smaller sub-arrays. Grouping is different than other JS array methods - it's *not* a part of the array prototype, but a static method.

Group data by keys using JavaScript Array Grouping (Object.groupBy)

Learn how the latest JavaScript features can help you improve your codebase. 

Learn the Latest ECMAScript Features (ES2024, ES2023, ...)

To persist data for our like button feature we will need to run a server. Fly.io is a great service that has a free tier that we can use to accomplish just that. 

We will sign up and instantiate a Fly.io project in this lesson.

Create a fly.io Account and Prepare a Project for Deployment

Prevent JavaScript Object Tampering with the SES Library harden Function

Prevent Global Prototype Mutability in JavaScript with SES lockdown

Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

node

You can send any data from your response resolvers. Let's implement a video streaming functionality by responding with a `ReadableStream` with Mock Service Worker. As a cherry on top, you will learn how to transform that video stream to inject server-side latency and see how our application's player handles it.

Respond With a ReadableStream in MSW

When working with existing APIs, especially those you don't own, being able to take the original response and manipulate it can be a life-changer when iterating on features or reproducing bugs. In this lesson, you will learn to perform the original request and then use Mock Service Worker to patch it with whichever data you want.

- [`bypass()`](https://mswjs.io/docs/recipes/response-patching)

Combine Original and Mocked Responses in MSW

Mocking responses is great but what if you want to observe requests without affecting them? In this lesson, we will learn how to instruct Mock Service Worker to perform intercepted requests as-is.

- [`passthrough()`](https://mswjs.io/docs/api/passthrough)

Perform Intercepted Requests As-Is in MSW

GraphQL is a query language for APIs and a runtime for fulfilling those queries with your existing data. GraphQL provides a complete and understandable description of the data in your API, gives clients the power to ask for exactly what they need and nothing more, makes it easier to evolve APIs over time, and enables powerful developer tools.

graphql

When your application communicates with multiple GraphQL services, it becomes problematic to distinguish them by operation type and name alone. Learn how to take the service's endpoint into account when intercepting GraphQL queries and mutations with Mock Service Worker.

- [`graphql.link()`](https://mswjs.io/docs/api/graphql#graphqllinkurl)

Endpoint-Based GraphQL Mocking in MSW

Let's improve our schema-first GraphQL mocks by intercepting _all_ GraphQL operations—both queries and mutations—using a single Mock Service Worker `graphql.operation()` request handler. 

- [`graphql.operation()`](https://mswjs.io/docs/api/graphql#graphloperationresolver)

Mock All GraphQL Operations in MSW

Operation-based GraphQL mocking allows you to move fast without investing time into schemas or resolvers. 

But, when integrating Mock Service Worker into an existing application, going schema-first can be advantageous. Here's how you can route every GraphQL request to be resolved against a GraphQL schema, mocked or real, and use mock resolvers to control individual types and fields. 

Resolve GraphQL Requests Against a Mock Schema in MSW

Error responses in GraphQL are a bit unique. They must still produce a "200 OK" response and list the errors in the response body instead. Let's follow the GraphQL specification to produce a valid GraphQL error response in our Mock Service Worker handlers. 

Mock GraphQL Errors in MSW

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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