Svelte

Svelte 4 Launch Party Recap

Published Jun 30, 2023

Updated Oct 12, 2023

12 min read

In this Svelte 4 Launch Party event, our panelists discussed the release of Svelte 4.

In this wrap-up, we will talk about panel discussions with Svelte core team members, which is an in-depth exploration of the Svelte 4 release, highlighting its key features and performance enhancements. You can watch the full Svelte 4 Launch Party event on the This Dot Media's YouTube channel.

Here is a complete list of the host and panelists that participated in this online event:

Hosts:

Tracy Lee, CEO, This Dot, @ladyleet
Rob Ocel, Team Lead & Software Architect, This Dot, @robocell

Panelists:

Geoff Rich, Svelte Core Team, @geoffrich_
Simon Holthausen, Full-time Svelte maintainer, @dummdidumm_
Puru Vijay, Svelte Core Team, @puruvjdev
Benn McCann, SvelteKit Maintainer, @BenjaminMcCann

Introductions

Geoff, one of the Svelte maintainers, started the introductions. He expressed his excitement about the new major version of Svelte and shared his years of experience using the framework. In his day job, Geoff is a Senior Software Engineer at Ordergroove.

Simon, a full-time Svelte maintainer working at Vercel, was busy preparing and finally releasing Svelte 4. He happily noted that there were very few bugs, and everything seemed to be working smoothly. Simon's dedication to maintaining the framework has contributed significantly to its success.

Puru, a college student, showcased his impressive skills by working on the website and the REPL for Svelte. Balancing his studies with web development, Puru demonstrated his passion for Svelte and his contributions to its ecosystem.

Ben primarily focuses on Svelte Kit, but also pitched in with Svelte 4. Besides his work on Svelte, Ben is an entrepreneur, adding an extra dimension to his diverse skill set. His contributions to the Svelte community have been invaluable.

What Should Everyone Be Excited About in Svelte 4?

Svelte 4 has arrived, and while it may not be packed with mind-blowing features, there are several neat little improvements that are worth getting excited about. The main focus of this release was on maintenance and cleaning up the framework to pave the way for the big Svelte 5 release. So don't worry, there are bigger things in the pipeline!

One of the first things to note is that file sizes in Svelte 4 have significantly decreased by about 10 to 12 fold. This means that your website will load much faster, thanks to the reduced bundle size. Additionally, improvements have been made in hydration, which affects the speed at which pages hydrate. The core around hydration has become smaller, resulting in improved performance.

Another noteworthy enhancement in Svelte 4 is the complete overhaul of custom element support. This change, although technically a breaking one, introduces a new wrapper approach. Previously, in Svelte 3, you had to use every Svelte component as a custom element, even if you wanted to keep certain components as internal implementation details. With the wrapper approach, you now have the flexibility to use components as regular Svelte components internally, fixing a range of bugs and fulfilling numerous feature requests. This change proved to be a tremendous success, resolving multiple issues in one fell swoop.

Svelte 4 brings value to your day-to-day development experience. For example, the improved type generation and autocomplete have made working with Svelte components a lot smoother. The autocomplete feature now grabs the correct import, eliminating the frustrations of navigating to the wrong files. Additionally, the introduction of declaration maps allows you to see the actual source code, providing a better understanding of the inner workings of Svelte.

There's also good news for those who want to contribute to the Svelte codebase. In Svelte 4, the entire codebase has been converted from TypeScript to JavaScript with JS Docs. While type checking is still in place to ensure error-free development, this change simplifies the process of working with the source code. Developers can now directly edit the source and test changes without worrying about the mapping between TypeScript and JavaScript.

In terms of performance, the reduction in bundle sizes has made a significant impact. Although the size reduction percentage may have been misunderstood by some, primarily referring to the compiler size rather than the runtime bundle, it has tangible benefits in scenarios like online tutorials and interactive experiences.

Beyond the technical improvements, Svelte 4 also brings updates to the documentation site and the main website. The team has put in considerable effort to enhance the user experience, making it easier to navigate and find the information you need.

Puru Does a Run Through of the Updates to the Svelte.dev Site

Puru shares exciting news to share about the overhaul of the svelte.dev website. First things first, let's talk about the star of the show: dark mode. It's finally here, and it's a game-changer. They’ve given the entire site a fresh redesign, taking inspiration from the sleek look of kit.svelte.dev. You'll notice some similarities, but they’ve added their own unique touch to make it shine. They’re now linking to the improved tutorial on learn.svelte.dev, which is definitely worth checking out.

Now, let's dive into the docs. They've made some significant changes to make your browsing experience a breeze. Instead of a single page, they've divided everything into multiple pages, making it super easy to find what you're looking for. Each component, logic block, and style module has its own dedicated page. It's all organized and up-to-date, thanks to the auto-generation from the source code. Say goodbye to outdated information and hello to hassle-free browsing.

They've introduced some fantastic new features that you're going to love. In the REPL, they've added multiple cursors, making coding even more efficient. Plus, they've created a REPL User Guide, packed with handy shortcuts and nifty tips and tricks. And here's the best part: our code snippets now support TypeScript. Just a simple click, and you'll have the TypeScript equivalent at your fingertips. It couldn't get any easier to level up your coding game!

So, head over to the new website, immerse yourself in the revamped docs, and enjoy all the fantastic updates we've made. And don't forget to check out the blog section for more in-depth information. Happy browsing, and get ready to experience the best of the new and improved website!

Upgrading from Svelte 3 to Svelte 4

Well there are a few things you need to know. But don't worry, it's not too complicated. First off, you'll find all the breaking changes highlighted and summarized on the migration Doc Page. So, if something breaks, you can check it out there.

If you're still on Svelte 3, the best way to start is by using the migration script. Just type in npx svelte-migrate svelte-4 in your command line, and it will go through your code base and automatically update things like tightened up types and local transitions. The migration script will even ask you if you want to migrate your global transitions or not. It's like a little questionnaire to make sure everything goes smoothly.

The migration script does a lot of the heavy lifting for you, updating dependencies in your package.json and ensuring peer dependency versions match up. It takes care of most things, but there might be a few other changes you'll need to handle. That's where the migration guide comes in handy. It covers all the other changes and helps you navigate through them.

Now keep in mind that upgrading to Svelte 4 might require at least Node 16. So, if you're using older dependencies that are holding you back from upgrading Node, it's time to poke your manager or tech lead and emphasize the need to stay current. After all, using outdated versions can pose security vulnerabilities. So make a strong case for the upgrade and let them know it's time to invest in keeping things up to date.

Geoff talked about how he has already upgraded a few sites to Svelte 4, and honestly, just upgraded the dependencies, and it worked like a charm. He didn't even bother running the migration script himself. Different projects may have different needs, so it's always good to be aware of any potential obstacles. Stay up to date and remember, keeping things secure is a top priority!

Svelte 4 and How It Works with Svelte Kit

If you're using Svelte Kit and thinking about upgrading to Svelte 4, here's what you need to know. The good news is that you can stick with your current version of Svelte Kit if you want, but there will be a warning about the peer dependencies not matching up. We made a small change to officially support Svelte 4 within Svelte Kit. But other than that, not much else has changed.

One important thing to remember is to upgrade the plugins file that Svelte Kit uses. You can do this by updating your lock file or simply upgrading to the latest Svelte Kit, which will take care of it for you. The migration script handles all the necessary updates, so running it will ensure everything works smoothly.

When it comes to impact, Svelte 4 brings some improvements. Your hydration code will be smaller, and the hydration speed will be faster, which means your final app bundle could be around 10% smaller. We've been working on even more performance enhancements, and using the Chrome performance tab in the developer tools can help you identify areas that need improvement.

So, in a nutshell, upgrading to Svelte 4 is optional for Svelte Kit users. But, it brings benefits like smaller code and faster hydration. Just remember to update the plugins file and use the migration script to handle any necessary changes. Keep an eye on the Chrome performance tab for optimization opportunities.

Are Svelte and Svelte Kit Going to be Paired in the Future in Updates or Stay Independent?

When it comes to updates for Svelte and Svelte Kit, there's a relationship between the two, but they also have their own focuses. The development of Svelte and Svelte Kit is somewhat interconnected, with learnings and improvements transferring between them. While the maintainers tend to focus on one major project at a time to gather feedback and make meaningful changes, they do draw lessons from both and apply them accordingly. For example, the decision to make transitions local by default in Svelte 4 stemmed from insights gained during the development of Svelte Kit.

Although there may be periods of emphasis on either Svelte or Svelte Kit, they are designed to complement each other and take advantage of each other's features. The development teams work on both code bases, ensuring a coordinated approach. While there may be a Svelte Kit 2 in the future, it's important to note that the release of Svelte 5 doesn't automatically mean a corresponding major update for Svelte Kit. The decision to introduce a new version depends on various factors, such as API changes and compatibility with the latest versions of Svelte, Node.js, and bundlers.

Ultimately, the goal is to provide a seamless and optimized experience for developers using Svelte and Svelte Kit. By developing them in tandem and leveraging the benefits of each, the teams behind these projects ensure continuous improvements and adaptability to the evolving needs of the community.

Svelte Dev Tools Repo and Funding for Svelte

So, regarding the Svelte Dev Tools repo, it used to be a community-maintained project led by a contributor named Red Hatter. She developed and published it independently. But more recently, she transferred the repository to the Svelte team so that they could also contribute and provide support. Currently, the team hasn't been able to publish new versions of the extension to the store, so there might still be the Svelte 3 version available. However, they are working on publishing a new version and may ask users to switch over to it for Svelte 4.

Now, let's talk about funding for Svelte. While financial support is definitely appreciated, the team also values something equally important—time. Companies can make a significant impact by allowing their employees to work on Svelte or Svelte Kit, fixing bugs, and contributing their time and expertise to improving the projects. Donations are welcome, of course, but finding skilled developers like Pooria (one of the Svelte team members) can be challenging even with funding available. So, giving employees the time and freedom to work on Svelte-related projects is highly appreciated and can have a significant positive impact. It's not just about money; it's about investing resources, whether financial or human, into the growth and development of the Svelte community.

Getting Involved in Open Source

If you're interested in getting involved in open source for Svelte, the journey can take different paths. One way to start is by creating projects or contributing to existing ones in the Svelte ecosystem. For example, Peru mentioned that he initially created a Svelte version of a tool called MacOS, which gained attention and led to him becoming a Svelte ambassador. Being active in the community, showcasing your work, and advocating for Svelte through speaking engagements or participating in events like Svelte Summit can also help raise your profile.

Becoming a Svelte ambassador or being recognized by the core team doesn't necessarily require direct contributions to the Svelte codebase. You can contribute in various ways, such as creating engaging content like videos or blog posts that benefit the community, maintaining popular Svelte libraries, assisting users on platforms like Discord or Stack Overflow, and participating in GitHub discussions. The core team and community value not only code contributions but also the positive impact and dedication you bring to the Svelte community.

It's worth noting that the journey can be unique for each person. Even if you haven't contributed to the Svelte codebase directly, like the ambassadors Hunter Byte and Joy of Code, you can still make a significant impact and be recognized for your contributions. For instance, Pooria mentioned that his first contribution was focused on creating the Svelte website rather than working on the core Svelte codebase. So, anyone with a passion for Svelte and a willingness to contribute can become a Svelte ambassador and actively participate in the open-source community.

Contributing to Open Source

Contributing to open-source projects like Svelte may seem daunting, but you don't have to understand the entire codebase from the start. Start by looking for beginner-friendly issues labeled as "good first issue" or similar tags. These provide a starting point to dive into the codebase. Follow the code path, use failing tests as guidance, and utilize features like control-clicking to navigate to relevant implementations.

Documentation and contribution guides are valuable resources for newcomers. Svelte Kit, for instance, has focused on making its codebase beginner-friendly. If you encounter difficulties, join the project's Discord channel and seek guidance from experienced contributors. Providing feedback on areas where more documentation is needed can help improve the contributor experience.

You can also contribute to adjacent tools related to Svelte, such as Prettier or ESLint plugins, which are maintained by the core team. These projects are often smaller in size and provide a manageable entry point. Additionally, non-coding contributions like improving project workflows or setting up testing and CI processes are also valuable.

Remember that contributions, regardless of their scale, have a positive impact on the project and the open-source community. Focus on understanding the specific area you want to work on, leverage available resources, engage with the community, and consider contributing to adjacent projects. With these steps, you can jump into contributing to open source and start making a difference.

Closing Thoughts from Panelists

Simon shared his enthusiasm for the future of Svelte, particularly the highly anticipated Svelte 5. The recent addition of Dominic to the team has already made a significant impact, and the brainstorming sessions have been rewarding. Exciting things are on the horizon for Svelte users.

Geoff encouraged everyone to give Svelte 4 a try and welcomes feedback and issue reports as they continue to refine and improve the framework. He emphasized that they are still in the early stages after the release and appreciate the community's support in upgrading their apps and providing valuable insights.

Peru gave a special shout-out to Paulo Ricca, who has been instrumental in resolving issues with the new REPL. With Paulo's assistance, the REPL is now as stable and impressive as before. Peru expresses his gratitude for the collaboration.

Ben extended his appreciation to the ecosystem integrations, mentioning the Storybook team and Jesse Beech, who contributed to optimizing file sizes and ensuring Svelte's compatibility with other JavaScript projects. The Svelte team is open to supporting and collaborating with anyone seeking to integrate Svelte with other tools in the ecosystem.

Overall, the panelists were thankful, excited about the future, and grateful for the community's contributions and collaborations. The energy and positive feedback drove their motivation, and they encouraged everyone to continue exploring and pushing the boundaries of what Svelte can achieve.

Conclusion

In this Svelte 4 Launch Party, the panelists express their gratitude to the vibrant Svelte community for their unwavering support and positive energy. The launch of Svelte 4 and the promising developments of Svelte 5 have generated excitement and anticipation among developers. The core team's commitment to continuous improvement, collaboration with ecosystem integrations, and dedication to addressing user feedback are evident. As Svelte evolves, the contributions of individuals, whether through code, documentation, or community engagement, are valued and celebrated. With the momentum and enthusiasm surrounding Svelte, the future looks bright for this innovative framework and its passionate community.

This Dot is a consultancy dedicated to guiding companies through their modernization and digital transformation journeys. Specializing in replatforming, modernizing, and launching new initiatives, we stand out by taking true ownership of your engineering projects.

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About the author(s)

Bruce Wiggleston
@brucerw3 @BruceRW3

A Deep Dive into SvelteKit's Rendering Techniques

A Deep Dive into SvelteKit's Rendering Techniques Introduction SvelteKit is a meta-framework for Svelte that allows you to develop pages based on their content. At its core, SvelteKit introduces three fundamental strategies out of the box, each designed to streamline the development process and adapt to the specific needs of your project. These strategies enable you to easily create dynamic, responsive, and highly interactive web applications. These strategies, or as SvelteKit calls them, page options, are: * Prerender: Ideal for static content that doesn't change, making your pages lightning-fast to load. * SSR (Server-Side Rendering): Ideal for rendering full pages with dynamic content from a server. * CSR (Client-Side Rendering): Best for highly dynamic and interactive applications where content updates frequently based on user actions. These page options can be applied to specific pages (when exported from **+page.js or +page.server.js) or to a group of pages (when exported from +layout.js or +layout.server.js). They can also be set across the entire application. You accomplish this by exporting it from the root layout. It's worth noting that child layouts and pages can supersede settings from parent layouts. This means you could activate prerendering for the whole app and then turn it off for certain pages that require dynamic server rendering (SSR). In this blog post, we'll explore these page options and share some insights on how you might use them in everyday web projects. Prerendering Prerendering is akin to taking a snapshot of your web pages when you build your application; you might have heard of this as static rendering. This snapshot is then served to all users, ensuring lightning-fast load times since the server simply delivers the pre-built files without additional processing rather than dynamically generating the files for each request. This method is perfect for content that remains unchanged across visits, such as blog posts, documentation, or landing pages. In other words, pages with no dynamic content. There will be situations where you would like to avoid using this option, though. The rule of thumb is that if two different users will see different content, then this is a no-go. Other reasons are inconvenience for your needs. For example, your build times could drag if you end up prerendering tons of pages. Is that convenient to you? Well, that’s for you to decide! The prerender option is turned off by default, so we need to enable it if we want to start using it. Export the following in the +page.server.js or just +page.js: ` Likewise, if you have a group of pages, you could do the same inside a +layout.js or +layout.server.js . If your app is suitable to be all SSG (Static Side Generation), you could use adapter-static, which will output files suitable for use with any static web server. In cases where you happen to opt-in for this, you could turn off pages that need dynamic rendering: ` Another cool feature about prerendering is that pages that fetch data from server routes can automatically inherit default values during the prerendering process. This feature simplifies data management and enhances the development workflow, especially when dealing with dynamic content that needs to be prerendered with specific data sets. Let's say you have a blog where each post fetches its content from a server route when the page loads. Normally, this would require the user's browser to make a request to the server at runtime. However, with prerendering, you can have this data fetched and embedded into the page at build time. ` In this example, when the blog/[slug].sveltepage is prerendered, it makes a fetch call to /api/posts/[slug], which returns the post data. This data is then used to prerender the blog post page with the content already in place, allowing the page to load instantly for the user, with the blog post content visible even before any JavaScript is executed on the client side. There’s a third and useful option when prerendering: ` Using this option is like telling SvelteKit to make a smart guess about whether to prerender your page in advance. You're saying, "Hey SvelteKit, you decide if this page should be prerendered based on what you find about the page" SvelteKit analyzes your page and if it determines the page can be prerendered without complications, it will automatically generate a prerendered version. This process involves SvelteKit either crawling a link inside an already prerendered page, prerendering entry points or targeting pages that are specifically marked for prerendering set in entries. An example is a blog section where you post articles regularly. The blog section has a main page that lists all your blog posts and individual pages for each blog post. The structure for this might be something like: In this setup, the /blog main entry page will be prerendered automatically. However, individual blog posts at paths like /blog/[slug] will not be prerendered unless linked directly from another prerendered page. For instance, if there’s a link to /blog/some-cool-slug, like: <a href="/blog/some-cool-slug">, SvelteKit will be able to crawl that link and prerender that specific page as well. Now let’s say that you would like to prerender your latest blog post, but there's no link for SvelteKit to crawl to this page. In these cases, you can explicitly add these pages to the prerender entries list. By doing so, SvelteKit will prerender every specified entry, ensuring that the content is immediately accessible to users. You can configure the prerender entries directly in your svelte.config.js file or by exporting an entries function from a +page.js, a +page.server.js or a +server.js belonging to a dynamic route. Here’s how you can do it: ` SSR SSR is similar to prerendering. It ensures that pages are first rendered on the server. This process generates the complete HTML content, which is then sent to the client for hydration). This approach enhances the initial page load performance and SEO, providing a better user experience. Unlike prerendering, where pages are generated at build time, SSR pages are created at runtime. This key difference allows for the generation of dynamic content, making SSR particularly suited for applications that require personalized content for each user or real-time updates, such as user dashboards, e-commerce sites, and social media platforms. Similar to prerendering, SSR comes with its own set of limitations, and there are scenarios where it might not be the best choice for your project: * SSR can be expensive. It can significantly load your server, especially for high-traffic sites, as each page request involves rendering content on the server. If server resources are constrained, this could lead to performance bottlenecks. * Highly Interactive Applications: Applications that rely heavily on user interactions and real-time updates (like games or interactive tools like an admin panel) might not benefit much from SSR. CSR can provide a smoother user experience in these cases, as it minimizes server requests after the initial load. * SEO Is Not YOUR Priority: If search engine optimization isn't a key concern for your project (for example, an internal dashboard or an app behind a login), the SEO benefits of SSR might not justify the additional complexity and server demands. export const ssr = true is the option enabled by default. Thus, we can use its benefits from the start. To execute code exclusively on the server, such as fetching data from a database or an external API, SvelteKit offers a convention using +page.server.js files. This setup is ideal for server-side operations, ensuring sensitive logic and credentials are not exposed to the client. ` Note: When you employ +page.js in SvelteKit, the contained code is executed on both the server and client sides by default. However, if you intend for the code to run exclusively on the client side, you can disable SSR by setting export const ssr = false within your +page.js file. Doing so ensures that the code is only executed in the browser, adhering to client-side rendering principles and turning your app into a SPA. This is useful for cases where you don’t need the load on the server, or you don’t benefit from any of the benefits of SSR. CSR CSR plays a crucial role in making web pages interactive by hydrating them and incorporating JavaScript. JavaScript is crucial for adding interactivity to web pages—everything from animations and video players to form validations and dynamic content updates relies on JavaScript. However, there are instances where JavaScript is unnecessary. Consider a prerendered 'About' page; enabling CSR on this page could be excessive, especially if it lacks interactive elements. In such scenarios, you can streamline your page by disabling CSR that comes enabled by default, which can be done by simply doing this: ` Using this trick smartly can make your web pages load fast because downloading JavaScript is sometimes heavy. The key lies in strategically combining this approach with other rendering techniques to optimize performance and user experience. One factor to consider, though, is that turning off CSR also means you'll lose client-side routing. This requires you to depend on traditional browser navigation instead. Conclusion By thoughtfully applying these strategies, you can craft a SvelteKit application that performs exceptionally and delivers a fantastic user experience tailored to your audience's needs. Wrapping up our journey through SSR with SvelteKit. We discovered how choosing the right way to render pages (like prerendering, SSR, or CSR) is super important and can make a big difference in how well a website works. SvelteKit is awesome because it lets you pick the best method for your website. So, remember, playing with SvelteKit and these rendering methods can make your websites stand out. Use it to build websites that not only work great but are also fun and easy for people to use. Dive in, try things out, and see how your web projects can shine!...

May 1, 2024

7 mins

SvelteSEOJavaScriptWeb Performance

Harnessing the Power of Threlte - Building Reactive Three.js Scenes in Svelte

Introduction Web development has evolved to include immersive 3D experiences through libraries like Three.js. This powerful JavaScript library enables the creation of captivating 3D scenes within browsers. Three.js: The 3D Powerhouse Three.js democratizes 3D rendering, allowing developers of all skill levels to craft interactive 3D worlds. Svelte Ecosystem: Svelte Cubed and Svelthree The Svelte ecosystem presents solutions like Svelte Cubed and Svelthree, which bridges Svelte with Three.js, offering streamlined reactivity for 3D web experiences. Introducing Threlte v6: Uniting SvelteKit 1.0, Svelte 4, and TypeScript Threlte v6 is a rendering and component library for Svelte that seamlessly integrates Three.js. By harnessing TypeScript's types, it provides a robust and delightful coding experience. In this tutorial, we'll showcase Threlte's capabilities by building an engaging website header: an auto-rotating sphere that changes color on mouse down. Using Threlte v6, SvelteKit 1.0, and Three.js, we're set to create a visually stunning experience. Let's dive in! Setting up Threlte Before building our scene, we need to set up Threlte. We can scaffold a new project using the CLI or manually install Threlte in an existing project. Option 1: Scaffold a New Threlte Project Create a new SvelteKit project and install Threlte with: ` Option 2: Manual Installation For an existing project, select the necessary Threlte packages and install: ` Configuration adjustments for SvelteKit can be made in the "vite.config.js" file: ` With Threlte configured, we're ready to build our interactive sphere. In the next chapter, we'll lay the groundwork for our exciting 3D web experience! Exploring the Boilerplate of Threlte Upon scaffolding a new project using npm create threlte, a few essential boilerplate files are generated. In this chapter, we'll examine the code snippets from three of these files: lib/components/scene.svelte, routes/+page.svelte, and lib/components/app.svelte. 1. lib/components/scene.svelte: This file lays the foundation for our 3D scene. Here's a brief breakdown of its main elements: - Perspective Camera: Sets up the camera view with a specific field of view and position, and integrates OrbitControls for auto-rotation and zoom management. - Directional and Ambient Lights: Defines the lighting conditions to illuminate the scene. - Grid: A grid structure to represent the ground. - ContactShadows: Adds shadow effects to enhance realism. - Float: Wraps around 3D mesh objects and defines floating properties, including intensity and range. Various geometrical shapes like BoxGeometry, TorusKnotGeometry, and IcosahedronGeometry are included here. 2. routes/+page.svelte: This file handles the ui of the index page and imports all necessary components we need to bring our vibrant design to life. 3. lib/components/app.svelte: This file is where you would typically define the main application layout, including styling and embedding other components. Heading to the Fun Stuff With the boilerplate components explained, we're now ready to dive into the exciting part of building our interactive 3D web experience. In the next section, we'll begin crafting our auto-rotating sphere, and explore how Threlte's robust features will help us bring it to life. Creating a Rotating Sphere Scene In this chapter, we'll walk you through creating an interactive 3D sphere scene using Threlte. We'll cover setting up the scene, the sphere, the camera and lights, and finally the interactivity that includes a scaling effect and color changes. 1. Setting Up the Scene First, we need to import the required components and utilities from Threlte. ` 2. Setting Up the Sphere We'll create the 3D sphere using Threlte's and components. ` 1. : This is a component from Threlte that represents a 3D object, which in this case is a sphere. It's the container that holds the geometry and material of the sphere. 2. : This is the geometry of the sphere. It defines the shape and characteristics of the sphere. The args attribute specifies the parameters for the sphere's creation: - The first argument (1) is the radius of the sphere. - The second argument (32) represents the number of width segments. - The third argument (32) represents the number of height segments. 3. : This is the material applied to the sphere. It determines how the surface of the sphere interacts with light. The color attribute specifies the color of the material. In this case, the color is dynamic and defined by the sphereColor variable, which updates based on user interaction. The roughness attribute controls the surface roughness of the sphere, affecting how it reflects light. 3. Setting Up the Camera and Lights Next, we'll position the camera and add lights to create a visually appealing scene. ` 1. : This component represents the camera in the scene. It provides the viewpoint through which the user sees the 3D objects. The position attribute defines the camera's position in 3D space. In this case, the camera is positioned at (-10, 20, 10). The fov attribute specifies the field of view, which affects how wide the camera's view is. - makeDefault: This attribute makes this camera the default camera for rendering the scene. 2. : This component provides controls for easy navigation and interaction with the scene. It allows the user to pan, zoom, and orbit around the objects in the scene. The attributes within the component configure its behavior: - enableZoom: Disables zooming using the mouse scroll wheel. - enablePan: Disables panning the scene. - enableDamping: Enables a damping effect that smoothens the camera's movement. - autoRotate: Enables automatic rotation of the camera around the scene. - autoRotateSpeed: Defines the speed of the auto-rotation. 3. : This component represents a directional light source in the scene. It simulates light coming from a specific direction. The attributes within the component configure the light's behavior: - intensity: Specifies the intensity of the light. - position.x and position.y: Define the position of the light source in the scene. 4. : This component represents an ambient light source in the scene. It provides even lighting across all objects in the scene. The intensity attribute controls the strength of the ambient light. 4. Interactivity: Scaling and Color Changes Now we'll add interactivity to the sphere, allowing it to scale and change color in response to user input. First, we'll import the required utilities for animation and set up a spring object to manage the scale. ` We'll update the sphere definition to include scaling: ` Lastly, we'll add code to update the color of the sphere based on the mouse's position within the window. ` We have successfully created a rotating sphere scene with scaling and color-changing interactivity. By leveraging Threlte's capabilities, we have built a visually engaging 3D experience that responds to user input, providing a dynamic and immersive interface. Adding Navigation and Scroll Prompt in app.svelte In this chapter, we'll add a navigation bar and a scroll prompt to our scene. The navigation bar provides links for user navigation, while the scroll prompt encourages the user to interact with the content. Here's a step-by-step breakdown of the code: 1. Importing the Canvas and Scene The Canvas component from Threlte serves as the container for our 3D scene. We import our custom Scene component to render within the canvas. ` 2. Embedding the 3D Scene The Canvas component wraps the Scene component to render the 3D content. It is positioned absolutely to cover the full viewport, and the z-index property ensures that it's layered behind the navigation elements. ` 3. Adding the Navigation Bar We use a element to create a horizontal navigation bar at the top of the page. It contains a home link and two navigation list items. The styling properties ensure that the navigation bar is visually appealing and positioned correctly. ` 4. Adding the Scroll Prompt We include a "Give a scroll" prompt with an element to encourage user interaction. It's positioned near the bottom of the viewport and styled for readability against the background. ` 5. Styling the Components Finally, the provided CSS styles control the positioning and appearance of the canvas, navigation bar, and scroll prompt. The CSS classes apply appropriate color, font, and layout properties to create a cohesive and attractive design. ` Head to the github repo to view the full code. Check out the result: https://threlte6-spinning-ball.vercel.app/ Conclusion We've successfully added navigation and a scroll prompt to our Threlte project in the app.svelte file. By layering 2D HTML content with a 3D scene, we've created an interactive user interface that combines traditional web design elements with immersive 3D visuals....

Aug 14, 2023

6 mins

Svelte

State of RxJS Wrap-up

In this State of RxJS event, our panelists discussed the current state of RxJS and the upcoming features and improvements of the highly anticipated RxJS 8 release. In this wrap-up, we will talk about panel discussions with RxJS core team members, which is an in-depth exploration of the upcoming RxJS 8 release, highlighting its key features and performance enhancements. You can watch the full State of RxJS event on the This Dot Media YouTube Channel. Here is a complete list of the host and panelists that participated in this online event. Hosts: - Tracy Lee, CEO, This Dot Labs, @ladyleet - Ben Lesh, RxJs Core Team Lead, @BenLesh Panelists: - Mladen Jakovljević, Frontend Web Developer, RxJS Core Team member, @jakovljeviMla - Moshe Kolodny, Senior Full Stack Engineer at Netflix, Previous RxJS Lead at Google, @mkldny - Marko Stanimirović, NgRx Core Team Member | GDE in Angular, @MarkoStDev State of RxJS Ben kicks off the discussion by updating everyone on the current state of RxJS. He starts off by recommending those using RxJS v6 to update to the current version 7.4 because it is about half the size of v6, and he says that v8 will reduce the size even further. There are also performance updates with 7.4 where the speeds improved 30 fold. RxJS version 8 is currently in alpha! There are not as many breaking changes with this version. The major breaking change in this version is that they are removing the long deprecated APIs. They are really wanting people to try things in the alpha version, especially the 408 loops to subscribe to observables. It is an interesting way to consume observables that use the platform, and may work really well with other people’s async await usage. Operators The team is currently trying to figure out a way to show people how they develop operators by giving them the means of developing operators. They currently have a problem where they externally tell people to develop an operator with this, you subscribe, and then you give this kind of hand rolled Observer there. Internally, they have a createOperatorSubscriber which replaces the operate function. They want a reference where you can see how to develop an operator using the ones already there to build your own. There is also a plan to make sure that the RxJS library works as a utility library to work with any Observable that matches the contract. Docs Mladen gives an update of the docs for RxJS. He explains that there aren’t a lot of updates currently with the docs. He explains that there were some issues in the past with exporting operators from two places. There was also an issue with the Docs app build running in the pipeline. He explains that these issues should now be resolved, and that there hopefully won’t be any more issues there. Pull requests are always welcome when working with RxJS docs. They try to stay on top of merge requests as well. NgRx Marko talks about NgRx and RxJS. He explains that RxJS is the main engine of NgRx for almost all of the libraries, especially State Management. A few packages, like direct store, implements a Redux pattern, but uses RxJS under the hood. Pipe Moshe brings up the typings for pipe. All of RxJS’s pipe methods and functions, including the new RxJS function, will work with any unary function. General Questions One of the first questions brought up was if RxJS should not be associated with Angular anymore. Ben brings up the fact that recently, there have been a lot of React people downloading RxJS. Another question was why NgRx is switching to Signals. Marco talks about how NgRx is a group of libraries that is used in Angular. NgRx needs to be in accordance with Angular. One main reason is because of the performance improvements with the change detection strategy. There were also other questions about contributing to RxJS and coming up with a way to utilize the docs for that. There are also questions about the RxJS community, and that there currently isn’t a discord or anything like that for it right now. Conclusion The panelists were very engaged, and there was a lot of dialogue about RxJS and the future that is to come with it. The question and answer portion at the end covered some great material that all the panelists took part in answering. You can watch the full State of RxJS event on the This Dot Media Youtube Channel....

May 22, 2023

4 mins

RxJS

Introduction to Zod for Data Validation

As web developers, we're often working with data from external sources like APIs we don't control or user inputs submitted to our backends. We can't always rely on this data to take the form we expect, and we can encounter unexpected errors when it deviates from expectations. But with the Zod library, we can define what our data ought to look like and parse the incoming data against those defined schemas. This lets us work with that data confidently, or to quickly throw an error when it isn't correct. Why use Zod? TypeScript is great for letting us define the shape of our data in our code. It helps us write more correct code the first time around by warning us if we are doing something we shouldn't. But TypeScript can't do everything for us. For example, we can define a variable as a string or a number, but we can't say "a string that starts with user_id_ and is 20 characters long" or "an integer between 1 and 5". There are limits to how much TypeScript can narrow down our data for us. Also, TypeScript is a tool for us developers. When we compile our code, our types are not available to the vanilla JavaScript. JavaScript can't validate that the data we actually use in our code matches what we thought we'd get when we wrote our TypeScript types unless you're willing to manually write code to perform those checks. This is where we can reach for a tool like Zod. With Zod, we can write data schemas. These schemas, in the simplest scenarios, look very much like TypeScript types. But we can do more with Zod than we can with TypeScript alone. Zod schemas let us create additional rules for data parsing and validation. A 20-character string that starts with user_id_? It's z.string().startsWith('user_id_').length(20). An integer between 1 and 5 inclusive? It's z.number().int().gte(1).lte(5). Zod's primitives give us many extra functions to be more specific about *exactly* what data we expect. Unlike TypeScript, Zod schemas aren't removed on compilation to JavaScript—we still have access to them! If our app receives some data, we can verify that it matches the expected shape by passing it to your Zod schema's parse function. You'll either get back your data in exactly the shape you defined in your schema, or Zod will give you an error to tell you what was wrong. Zod schemas aren't a replacement for TypeScript; rather, they are an excellent complement. Once we've defined our Zod schema, it's simple to derive a TypeScript type from it and to use that type as we normally would. But when we really need to be sure our data conforms to the schema, we can always parse the data with our schema for that extra confidence. Defining Data Schemas Zod schemas are the variables that define our expectations for the shape of our data, validate those expectations, and transform the data if necessary to match our desired shape. It's easy to start with simple schemas, and to add complexity as required. Zod provides different functions that represent data structures and related validation options, which can be combined to create larger schemas. In many cases, you'll probably be building a schema for a data object with properties of some primitive type. For example, here's a schema that would validate a JavaScript object representing an order for a pizza: ` Zod provides a number of primitives for defining schemas that line up with JavaScript primitives: string, number, bigint, boolean, date, symbol, undefined, and null. It also includes primitives void, any, unknown, and never for additional typing information. In addition to basic primitives, Zod can define object, array, and other native data structure schemas, as well as schemas for data structures not natively part of JavaScript like tuple and enum. The documentation contains considerable detail on the available data structures and how to use them. Parsing and Validating Data with Schemas With Zod schemas, you're not only telling your program what data should look like; you're also creating the tools to easily verify that the incoming data matches the schema definitions. This is where Zod really shines, as it greatly simplifies the process of validating data like user inputs or third party API responses. Let's say you're writing a website form to register new users. At a minimum, you'll need to make sure the new user's email address is a valid email address. For a password, we'll ask for something at least 8 characters long and including one letter, one number, and one special character. (Yes, this is not really the best way to write strong passwords; but for the sake of showing off how Zod works, we're going with it.) We'll also ask the user to confirm their password by typing it twice. First, let's create a Zod schema to model these inputs: ` So far, this schema is pretty basic. It's only making sure that whatever the user types as an email is an email, and it's checking that the password is at least 8 characters long. But it is *not* checking if password and confirmPassword match, nor checking for the complexity requirements. Let's enhance our schema to fix that! ` By adding refine with a custom validation function, we have been able to verify that the passwords match. If they don't, parsing will give us an error to let us know that the data was invalid. We can also chain refine functions to add checks for our password complexity rules: ` Here we've chained multiple refine functions. You could alternatively use superRefine, which gives you even more fine grained control. Now that we've built out our schema and added refinements for extra validation, we can parse some user inputs. Let's see two test cases: one that's bound to fail, and one that will succeed. ` There are two main ways we can use our schema to validate our data: parse and safeParse. The main difference is that parse will throw an error if validation fails, while safeParse will return an object with a success property of either true or false, and either a data property with your parsed data or an error property with the details of a ZodError explaining why the parsing failed. In the case of our example data, userInput2 will parse just fine and return the data for you to use. But userInput1 will create a ZodError listing all of the ways it has failed validation. ` ` We can use these error messages to communicate to the user how they need to fix their form inputs if validation fails. Each error in the list describes the validation failure and gives us a human readable message to go with it. You'll notice that the validation errors for checking for a valid email and for checking password length have a lot of details, but we've got three items at the end of the error list that don't really tell us anything useful: just a custom error of Invalid input. The first is from our refine checking if the passwords match, and the second two are from our refine functions checking for password complexity (numbers and special characters). Let's modify our refine functions so that these errors are useful! We'll add our own error parameters to customize the message we get back and the path to the data that failed validation. ` Now, our error messages from failures in refine are informative! You can figure out which form fields aren't validating from the path, and then display the messages next to form fields to let the user know how to remedy the error. ` By giving our refine checks a custom path and message, we can make better use of the returned errors. In this case, we can highlight specific problem form fields for the user and give them the message about what is wrong. Integrating with TypeScript Integrating Zod with TypeScript is very easy. Using z.infer<typeof YourSchema> will allow you to avoid writing extra TypeScript types that merely reflect the intent of your Zod schemas. You can create a type from any Zod schema like so: ` Using a TypeScript type derived from a Zod schema does *not* give you any extra level of data validation at the type level beyond what TypeScript is capable of. If you create a type from z.string.min(3).max(20), the TypeScript type will still just be string. And when compiled to JavaScript, even that will be gone! That's why you still need to use parse/safeParse on incoming data to validate it before proceeding as if it really does match your requirements. A common pattern with inferring types from Zod schemas is to use the same name for both. Because the schema is a variable, there's no name conflict if the type uses the same name. However, I find that this can lead to confusing situations when trying to import one or the other—my personal preference is to name the Zod schema with Schema at the end to make it clear which is which. Conclusion Zod is an excellent tool for easily and confidently asserting that the data you're working with is exactly the sort of data you were expecting. It gives us the ability to assert at runtime that we've got what we wanted, and allows us to then craft strategies to handle what happens if that data is wrong. Combined with the ability to infer TypeScript types from Zod schemas, it lets us write and run more reliable code with greater confidence....

Nov 15, 2024

7 mins

JavaScriptZod

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Svelte 4 Launch Party Recap

Introductions

What Should Everyone Be Excited About in Svelte 4?

Puru Does a Run Through of the Updates to the Svelte.dev Site

Upgrading from Svelte 3 to Svelte 4

Svelte 4 and How It Works with Svelte Kit

Are Svelte and Svelte Kit Going to be Paired in the Future in Updates or Stay Independent?

Svelte Dev Tools Repo and Funding for Svelte

Getting Involved in Open Source

Contributing to Open Source

Closing Thoughts from Panelists

Conclusion

Bruce Wiggleston

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A Deep Dive into SvelteKit's Rendering Techniques

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