VueJS

Nuxt DevTools v1.0: Redefining the Developer Experience Beyond Conventional Tools

Published Dec 1, 2023

Updated Dec 1, 2023

8 min read

In the ever-evolving world of web development, Nuxt.js has taken a monumental leap with the launch of Nuxt DevTools v1.0. More than just a set of tools, it's a game-changer—a faithful companion for developers. This groundbreaking release, available for all Nuxt projects and being defaulted from Nuxt v3.8 onwards, marks the beginning of a new era in developer tools. It's designed to simplify our development journey, offering unparalleled transparency, performance, and ease of use. Join me as we explore how Nuxt DevTools v1.0 is set to revolutionize our workflow, making development faster and more efficient than ever.

What makes Nuxt DevTools so unique?

Alright, let's start delving into the features that make this tool so amazing and unique. There are a lot, so buckle up!

In-App DevTools

The first thing that caught my attention is that breaking away from traditional browser extensions, Nuxt DevTools v1.0 is seamlessly integrated within your Nuxt app. This ensures universal compatibility across browsers and devices, offering a more stable and consistent development experience. This setup also means the tools are readily available in the app, making your work more efficient. It's a smart move from the usual browser extensions, making it a notable highlight.

To use it you just need to press Shift + Option + D (macOS) or Shift + Alt + D (Windows):

With simple keystrokes, the Nuxt DevTools v1.0 springs to life directly within your app, ready for action. This integration eliminates the need to toggle between windows or panels, keeping your workflow streamlined and focused. The tools are not only easily accessible but also intelligently designed to enhance your productivity.

Pages, Components, and Componsables View

The Pages, Components, and Composables View in Nuxt DevTools v1.0 are a clear roadmap for your app. They help you understand how your app is built by simply showing its structure. It's like having a map that makes sense of your app's layout, making the complex parts of your code easier to understand. This is really helpful for new developers learning about the app and experienced developers working on big projects.

Pages View lists all your app's pages, making it easier to move around and see how your site is structured. What's impressive is the live update capability. As you explore the DevTools, you can see the changes happening in real-time, giving you instant feedback on your app's behavior.

Components View is like a detailed map of all the parts (components) your app uses, showing you how they connect and depend on each other. This helps you keep everything organized, especially in big projects. You can inspect components, change layouts, see their references, and filter them. increment, decrement and reset button example

By showcasing all the auto-imported composables, Nuxt DevTools provides a clear overview of the composables in use, including their source files. This feature brings much-needed clarity to managing composables within large projects. You can also see short descriptions and documentation links in some of them.

Together, these features give you a clear picture of your app's layout and workings, simplifying navigation and management.

Modules and Static Assets Management

This aspect of the DevTools revolutionizes module management. It displays all registered modules, documentation, and repository links, making it easy to discover and install new modules from the community! This makes managing and expanding your app's capabilities more straightforward than ever.

On the other hand, handling static assets like images and videos becomes a breeze. The tool allows you to preview and integrate these assets effortlessly within the DevTools environment. preview and integrate static assets within nuxt dev tools

These features significantly enhance the ease and efficiency of managing your app's dynamic and static elements.

The Runtime Config and Payload Editor

The Runtime Config and Payload Editor in Nuxt DevTools make working with your app's settings and data straightforward.

The Runtime Config lets you play with different configuration settings in real time, like adjusting settings on the fly and seeing the effects immediately. This is great for fine-tuning your app without guesswork.

The Payload Editor is all about managing the data your app handles, especially data passed from server to client. It's like having a direct view and control over the data your app uses and displays. This tool is handy for seeing how changes in data impact your app, making it easier to understand and debug data-related issues.

Open Graph Preview

The Open Graph Preview in Nuxt DevTools is a feature I find incredibly handy and a real time-saver. It lets you see how your app will appear when shared on social media platforms. This tool is crucial for SEO and social media presence, as it previews the Open Graph tags (like images and descriptions) used when your app is shared. No more deploying first to check if everything looks right – you can now tweak and get instant feedback within the DevTools. This feature not only streamlines the process of optimizing for social media but also ensures your app makes the best possible first impression online.

Timeline

The Timeline feature in Nuxt DevTools is another standout tool. It lets you track when and how each part of your app (like composables) is called. This is different from typical performance tools because it focuses on the high-level aspects of your app, like navigation events and composable calls, giving you a more practical view of your app's operation. It's particularly useful for understanding the sequence and impact of events and actions in your app, making it easier to spot issues and optimize performance. This timeline view brings a new level of clarity to monitoring your app's behavior in real-time.

Production Build Analyzer

The Production Build Analyzer feature in Nuxt DevTools v1.0 is like a health check for your app. It looks at your app's final build and shows you how to make it better and faster. Think of it as a doctor for your app, pointing out areas that need improvement and helping you optimize performance.

API Playground

The API Playground in Nuxt DevTools v1.0 is like a sandbox where you can play and experiment with your app's APIs. It's a space where you can easily test and try out different things without affecting your main app. This makes it a great tool for trying out new ideas or checking how changes might work.

Some other cool features

Another amazing aspect of Nuxt DevTools is the embedded full-featured VS Code. It's like having your favorite code editor inside the DevTools, with all its powerful features and extensions. It's incredibly convenient for making quick edits or tweaks to your code.

Then there's the Component Inspector. Think of it as your code's detective tool. It lets you easily pinpoint and understand which parts of your code are behind specific elements on your page. This makes identifying and editing components a breeze.

And remember customization! Nuxt DevTools lets you tweak its UI to suit your style. This means you can set up the tools just how you like them, making your development environment more comfortable and tailored to your preferences.

Conclusion

In summary, Nuxt DevTools v1.0 marks a revolutionary step in web development, offering a comprehensive suite of features that elevate the entire development process. Features like live updates, easy navigation, and a user-friendly interface enrich the development experience. Each tool within Nuxt DevTools v1.0 is thoughtfully designed to simplify and enhance how developers build and manage their applications.

In essence, Nuxt DevTools v1.0 is more than just a toolkit; it's a transformative companion for developers seeking to build high-quality web applications more efficiently and effectively. It represents the future of web development tools, setting new standards in developer experience and productivity.

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About the author(s)

Jesús Padrón
@padron4497 @jesus4497

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

Exploring Angular Forms: A New Alternative with Signals

Exploring Angular Forms: A New Alternative with Signals In the world of Angular, forms are essential for user interaction, whether you're crafting a simple login page or a more complex user profile interface. Angular traditionally offers two primary approaches: template-driven forms and reactive forms. In my previous series on Angular Reactive Forms, I explored how to harness reactive forms' power to manage complex logic, create dynamic forms, and build custom form controls. A new tool for managing reactivity - signals - has been introduced in version 16 of Angular and has been the focus of Angular maintainers ever since, becoming stable with version 17. Signals allow you to handle state changes declaratively, offering an exciting alternative that combines the simplicity of template-driven forms with the robust reactivity of reactive forms. This article will examine how signals can add reactivity to both simple and complex forms in Angular. Recap: Angular Forms Approaches Before diving into the topic of enhancing template-driven forms with signals, let’s quickly recap Angular's traditional forms approaches: 1. Template-Driven Forms: Defined directly in the HTML template using directives like ngModel, these forms are easy to set up and are ideal for simple forms. However, they may not provide the fine-grained control required for more complex scenarios. Here's a minimal example of a template-driven form: ` ` 2. Reactive Forms: Managed programmatically in the component class using Angular's FormGroup, FormControl, and FormArray classes; reactive forms offer granular control over form state and validation. This approach is well-suited for complex forms, as my previous articles on Angular Reactive Forms discussed. And here's a minimal example of a reactive form: ` ` Introducing Signals as a New Way to Handle Form Reactivity With the release of Angular 16, signals have emerged as a new way to manage reactivity. Signals provide a declarative approach to state management, making your code more predictable and easier to understand. When applied to forms, signals can enhance the simplicity of template-driven forms while offering the reactivity and control typically associated with reactive forms. Let’s explore how signals can be used in both simple and complex form scenarios. Example 1: A Simple Template-Driven Form with Signals Consider a basic login form. Typically, this would be implemented using template-driven forms like this: ` ` This approach works well for simple forms, but by introducing signals, we can keep the simplicity while adding reactive capabilities: ` ` In this example, the form fields are defined as signals, allowing for reactive updates whenever the form state changes. The formValue signal provides a computed value that reflects the current state of the form. This approach offers a more declarative way to manage form state and reactivity, combining the simplicity of template-driven forms with the power of signals. You may be tempted to define the form directly as an object inside a signal. While such an approach may seem more concise, typing into the individual fields does not dispatch reactivity updates, which is usually a deal breaker. Here’s an example StackBlitz with a component suffering from such an issue: Therefore, if you'd like to react to changes in the form fields, it's better to define each field as a separate signal. By defining each form field as a separate signal, you ensure that changes to individual fields trigger reactivity updates correctly. Example 2: A Complex Form with Signals You may see little benefit in using signals for simple forms like the login form above, but they truly shine when handling more complex forms. Let's explore a more intricate scenario - a user profile form that includes fields like firstName, lastName, email, phoneNumbers, and address. The phoneNumbers field is dynamic, allowing users to add or remove phone numbers as needed. Here's how this form might be defined using signals: ` > Notice that the phoneNumbers field is defined as a signal of an array of signals. This structure allows us to track changes to individual phone numbers and update the form state reactively. The addPhoneNumber and removePhoneNumber methods update the phoneNumbers signal array, triggering reactivity updates in the form. ` > In the template, we use the phoneNumbers signal array to dynamically render the phone number input fields. The addPhoneNumber and removePhoneNumber methods allow users to reactively add or remove phone numbers, updating the form state. Notice the usage of the track function, which is necessary to ensure that the ngFor directive tracks changes to the phoneNumbers array correctly. Here's a StackBlitz demo of the complex form example for you to play around with: Validating Forms with Signals Validation is critical to any form, ensuring that user input meets the required criteria before submission. With signals, validation can be handled in a reactive and declarative manner. In the complex form example above, we've implemented a computed signal called formValid, which checks whether all fields meet specific validation criteria. The validation logic can easily be customized to accommodate different rules, such as checking for valid email formats or ensuring that all required fields are filled out. Using signals for validation allows you to create more maintainable and testable code, as the validation rules are clearly defined and react automatically to changes in form fields. It can even be abstracted into a separate utility to make it reusable across different forms. In the complex form example, the formValid signal ensures that all required fields are filled and validates the email and phone numbers format. This approach to validation is a bit simple and needs to be better connected to the actual form fields. While it will work for many use cases, in some cases, you might want to wait until explicit "signal forms" support is added to Angular. Tim Deschryver started implementing some abstractions around signal forms, including validation and wrote an article about it. Let's see if something like this will be added to Angular in the future. Why Use Signals in Angular Forms? The adoption of signals in Angular provides a powerful new way to manage form state and reactivity. Signals offer a flexible, declarative approach that can simplify complex form handling by combining the strengths of template-driven forms and reactive forms. Here are some key benefits of using signals in Angular forms: 1. Declarative State Management: Signals allow you to define form fields and computed values declaratively, making your code more predictable and easier to understand. 2. Reactivity: Signals provide reactive updates to form fields, ensuring that changes to the form state trigger reactivity updates automatically. 3. Granular Control: Signals allow you to define form fields at a granular level, enabling fine-grained control over form state and validation. 4. Dynamic Forms: Signals can be used to create dynamic forms with fields that can be added or removed dynamically, providing a flexible way to handle complex form scenarios. 5. Simplicity: Signals can offer a simpler, more concise way to manage form states than traditional reactive forms, making building and maintaining complex forms easier. Conclusion In my previous articles, we explored the powerful features of Angular reactive forms, from dynamic form construction to custom form controls. With the introduction of signals, Angular developers have a new tool that merges the simplicity of template-driven forms with the reactivity of reactive forms. While many use cases warrant Reactive Forms, signals provide a fresh, powerful alternative for managing form state in Angular applications requiring a more straightforward, declarative approach. As Angular continues to evolve, experimenting with these new features will help you build more maintainable, performant applications. Happy coding!...

Oct 4, 2024

5 mins

AngularJavaScript

Exploring the Hidden Gems of the Next Image Component: What You Might Be Overlooking

Welcome to a journey of discovery where we'll explore the often-overlooked capabilities of the Next.js Image component. At first glance, this component might seem like a straightforward tool, merely enhancing performance compared to a regular img tag. However, there's more to it than meets the eye. In this blog post, we'll uncover the magic of some features of the Next.js Image component. It's easy to use, yes, but it also packs a punch with features that go beyond simple image rendering. These hidden features can significantly impact your project, and missing them could mean not fully utilizing the component's potential. Let's dive into this exploration, unraveling the subtle yet powerful aspects of the Next.js Image component that are easy to overlook. So, without further delay, let's get started! Size First up, let's chat about width and height. These are rules for how big your image shows on the screen. You gotta use them most of the time. But hey, if you're pulling in an image directly into your code (that's what we call 'static importing') or you want your image to just fill up whatever space it's in (using the 'fill' prop), then you can skip these rules. Neat, right? But that's not all there's to it. You see, when Next.js fetches the image from the server, it does something behind the scenes. It doesn’t just grab any size of the image. Instead, Next.js is smart and picks the best size that fits the spot on your webpage. This means your images load faster and look just right, whether on a big desktop screen or a small phone screen. It's like having a personal assistant for your images, making sure they are always looking their best and not slowing down your site. Here's a part that's easy to miss: Next.js uses a feature called 'srcset' to decide which image size to download from the server. By default, Next.js uses the following default: ` So, imagine you have an image that's 75 pixels wide. Next.js will look at this list and pick the closest size. In our case, with these default settings, it would download the 96-pixel version. This occurs because Next.js selects the smallest available size from the list that exceeds the original's width, ensuring the image remains clear on all devices; even if your image is a bit smaller or larger, Next.js picks the nearest size from this list. This is important to know because if you are looking to get the most performant image possible, you should be aware of these size values. By understanding how Next.js selects the image size, you can better tailor your images to match these presets. This way, you ensure that your site is not only loading the appropriate image size for different devices but also optimizing for speed and efficiency. Keeping an eye on these sizes helps you balance between image quality and fast loading times, which is key for a great user experience on your site. Quality Now, let's highlight something about image quality. It's often overlooked, but by default, Next.js sets the image quality to 75. Sure, you can tweak this with the quality prop, but here's the catch: bumping up the quality to 100 will significantly increase the image's file size. This means your images will look super sharp, but they'll also take longer to load. It's all about finding that sweet spot where your images look great without slowing down your website. Remember, a faster site often means a better experience for your visitors. My advice is to always check what is better for you in each situation. Ask yourself: Consider whether it's more beneficial to opt for larger images at a slightly reduced quality, in alignment with the “srcset” configurations we explored, or if it's preferable to enhance the image quality, even if it means working with smaller dimensions? It's a balancing act. Usually, cranking up the quality to 100 isn't the best move because it makes the image file really big, which can slow down your site. It's all about making smart choices. Go for a quality that makes your images look good without burdening your site's load time. Sometimes, a slightly lower quality image, but well optimized, can be way more effective than a perfect but sluggish, high-quality image. Loader The loader prop in Next.js is a key player. It's not just about fetching images; it’s about fetching them smartly and securely. When using images from different places, like a CMS or your server, the loader prop helps you manage them efficiently and safely. For instance, say you have images on Contentful. Next.js doesn't automatically know the best way to fetch these, but with a custom loader, you can define this process. This loader optimizes your images, selecting the right format, width, and quality. Your images not only look great but load faster, too. Remember, when fetching images from external sources, it's crucial to use remotePatterns (inside your next.config file) for security reasons. This ensures your site stays safe while handling images from outside. This approach is scalable and saves time. You set up the loader once, and it works for all your images, making your site efficient and your code neat. Here’s an example: ` ` Placeholder Prop A little-known yet impactful feature of the Next.js Image component is the placeholder prop. It's all about improving the user experience while your images are loading. Imagine visiting a website and waiting for images to load – it can be a bit dull, right? The placeholder prop can make this wait a lot more pleasant. You can use this prop to display a blur effect or a solid color before the image fully loads. This creates a smoother visual experience. The blur placeholder is particularly popular because it gives a sneak peek of the image without revealing all the details. It's like a teaser, building anticipation for what's to come. Here’s how you can use it: ` In this example, blurDataURL is a small, low-quality version of your image that loads much faster. Once the actual image is ready, it seamlessly replaces the blur. This approach significantly enhances the perceived loading speed and keeps your users engaged. Incorporating the placeholder prop can make a big difference in how professional and polished your site feels, especially on slower connections where image load times are noticeable. Conclusion The Next.js Image component is a powerful tool that goes beyond simple image rendering. By understanding its hidden features and capabilities, you can optimize your project for performance and user experience. From utilizing the 'width' and 'height' properties to ensuring the right image quality and using the 'loader' prop for efficient image fetching, there are several aspects to consider. Additionally, the 'placeholder' prop can enhance the user experience by displaying a blur effect or solid color while images load. By exploring these often-overlooked features, you can unlock the full potential of the Next.js Image component and create a more engaging and optimized website....

Feb 9, 2024

5 mins

UXJavaScriptNextJS

Svelte 5 is Here!

Svelte 5 was finally released after a long time in development. Fortunately, we've been able to test it for some time, and now it has a stable release. Let's dig into its features and why this is such a significant change, even though Svelte 4 code is almost 100% compatible. Svelte syntax everywhere This is one of my favorite additions. Previously, Svelte syntax was limited to a component element. Refactoring code from a component and moving it to a JavaScript file worked differently. Now you can use the .svelte.js or .svelte.ts extension, which allows you to use the same syntax everywhere. It's important to note that it's a way to express that this is not just JS, and what you write may be compiled to something else, just like .svelte files are not just html even though they look very similar. Runes The introduction of runes is one of the most significant changes in Svelte. Many users felt attracted to variables being instantly reactive in previous versions. ` There was, however, a lot of magic underneath and a considerable amount of work from the compiler to make it behave reactively. $state In Svelte 5, a reactive variable has to be explicitly declared using the $state rune, which brings a clear distinction between what is reactive and what isn’t. ` In the previous code, $state is not an actual function being called; it's a hint for the compiler to do something special with this declaration. Rune names always start with a dollar sign ($) and do not need to be imported. However, there’s much more to the changes than just the way we declare reactive variables. Runes bring a lot of new features that make Svelte 5 a great improvement. In Svelte 5, objects or arrays use Proxies to allow for granular reactivity, meaning that individual properties in an object are reactive, even if they are nested objects or arrays. If you modify a property, it will only update that property and will not trigger an update on the whole object. It also supports triggering updates when methods like array.push are called. In previous versions, an assignment was required to trigger an update: ` To have a similar behavior of svelte 4 (no deep reactivity), use the $state.raw() rune. This syntax of .* is common for related features of a rune: $state.raw() will require an assignment to trigger reactivity. ` Because proxies are used, you may need to extract the underlying state instead of the proxy itself. In that case, $state.snapshot() should be used: ` $derived We will use $derived and $derived.by to declare a derived state. The two runes are essentially the same, except one allows us to use a function instead of an expression, allowing for more complex operations to calculate the derived values. ` $effect Effects are useful for running something triggered by a change in state. One of the things you'll note from the $effect rune is that dependencies don't need to be explicit. Those will be picked from reactive values read synchronously in the body of the effect function. ` Something to bear in mind is that these dependencies are picked each time the effect runs. The values read during the last run become the dependencies of the effect. ` Depending on the result of the random method, foo or bar will stop being a dependency of the effect. You should place them outside the condition so they can trigger reruns of the effect. *Variants* of the effect rune are $effect.pre, which runs before a DOM update, and $effect.tracking(), which checks for the context of the effect (true for an effect inside an effect or in the template). $props This rune replaces the export let keywords used in previous versions to define a component's props. To use the $props syntax, we can consider it to return an object with all the properties a component receives. We can use JavaScript syntax to destructure it or use the rest property if we want to retrieve every property not explicitly destructured.. ` $bindable If you want to mutate a prop so that the change flows back to the parent, you can use the $bindable prop to make it work in both directions. A parent component can pass a value to a child component, and the child component is able to modify it, returning the data back to the parent component. ` $inspect The $inspect rune only works in dev mode and will track dependencies deeply. By default, it will call console.log with the provided argument whenever it detects a change. To change the underlying function, use $inspect.with().with): ` $host The host rune gives access to the host element when compiling as a custom element: ` ` Other changes Another important change is that component events are just props in Svelte 5, so you can destructure them using the $props() rune: ` A special children property can be used to project content into a component instead of using slots. Inside the components, use the [@render[(https://svelte.dev/docs/svelte/@render) tag to place them. ` Optional chaining (?.) prevents from attempting to render it if no children are passed in. If you need to render different components in different places (named slots before Svelte 5, you can pass them as any other prop, and use @render with them. Snippets Snippets allow us to declare markup slices and render them conveniently using the render tag (@render). They can take any number of arguments. ` Snippets can also be passed as props to other components. ` ` Conclusion Some exciting changes to the Svelte syntax were introduced while, at the same time, maximum compatibility efforts were made. This was a massive rewrite with numerous improvements in terms of performance, bundle size, and DX. Besides that, a new CLI has been released, making the whole experience of starting a project or adding features delightful. If you haven't tried Svelte before, it's a great time to try it now....

Nov 27, 2024

4 mins

Svelte

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Nuxt DevTools v1.0: Redefining the Developer Experience Beyond Conventional Tools

What makes Nuxt DevTools so unique?

In-App DevTools

Pages, Components, and Componsables View

Modules and Static Assets Management

The Runtime Config and Payload Editor

Open Graph Preview

Timeline

Production Build Analyzer

API Playground

Some other cool features

Conclusion

Jesús Padrón

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