7 November 2025

If you’ve been dabbling in web development, you’ve probably heard about JavaScript frameworks like React, Vue, or Angular. But there’s a new kid on the block, and it’s making a lot of noise in the development world — Svelte. In this article, we’ll explore how to build web apps using Svelte and JavaScript. Don’t worry if you’re not an expert yet; I’ll take you through everything step-by-step, as if we’re sitting down together, with a cup of coffee, geeking out over code.

So, what’s the big deal with Svelte? How is it different from the other frameworks? And more importantly, how can you use it to create responsive, modern web applications? Let’s dive in!

What is Svelte?

Before you even start writing code, it’s important to understand what Svelte is and what makes it special.

Svelte is a JavaScript framework, much like React or Vue, but with a twist. Unlike other frameworks that do most of their work in the browser, Svelte shifts that work to build time. This means instead of shipping a framework to the browser and letting it handle everything, Svelte compiles your code into vanilla JavaScript. The result? Faster performance and smaller bundle sizes. Think of it as putting your web app on a diet — it runs lean and fast.

To put it simply, Svelte is like a chef that prepares all the meals in the kitchen (build time), so by the time the food (your web app) reaches the table (the browser), everything is ready to go, no extra cooking required. Other frameworks do a lot of their cooking right at the table, which can slow things down.

Why Choose Svelte Over Other Frameworks?

You might be asking yourself, "Why should I pick Svelte over something more established like React?" Good question!

- No Virtual DOM: Unlike React, Svelte doesn’t rely on a virtual DOM. Instead, it writes optimized JavaScript code that directly updates the DOM when the state of your app changes.
- Lightweight: Svelte apps are typically smaller in size, which means faster load times.
- Less Boilerplate: Svelte focuses on simplicity. You can write less code and achieve the same functionality compared to other frameworks.
- Reactive Design: Svelte’s reactivity is built-in. You don’t need to jump through hoops to manage state changes.

By moving the heavy lifting to compile time, your web apps become more efficient. Plus, with Svelte’s simple syntax and built-in reactivity, you'll find that you can build web apps faster, with fewer headaches.

Setting Up the Environment

Alright, now that we’ve covered the “why,” let’s get into the “how.” First things first, we need to set up our development environment.

Step 1: Install Node.js and npm

If you don’t have Node.js and npm (Node Package Manager) installed, you’ll need to get those first. Both are crucial for managing packages, including Svelte.

Head over to the official Node.js website, download the latest version, and follow the installation instructions. Once installed, you can verify the installation by running these commands in your terminal:

bash
node -v
npm -v

These commands should output the versions of Node.js and npm installed.

Step 2: Create a New Svelte Project

Now that you’ve got Node.js and npm up and running, let’s create our Svelte project. In your terminal, type the following command to set up a new Svelte project using the official template:

bash
npx degit sveltejs/template my-svelte-app

This command downloads the official Svelte template. Replace `my-svelte-app` with whatever name you want for your project folder.

Next, navigate to your project folder and install the necessary dependencies:

bash
cd my-svelte-app
npm install

Step 3: Start the Development Server

Once the installation is complete, you can start the development server by running:

bash
npm run dev

Open your browser and go to `http://localhost:5000`. You should see the default Svelte app running! ? You’re all set to start building.

Building Your First Svelte Component

Svelte is all about components. Each component is a self-contained piece of your application, complete with its own HTML, CSS, and JavaScript. It’s like building with Lego blocks — you can piece together various components to build a full-fledged app.

Let’s create a simple “Hello World” component.

Step 1: Create a New Component

Inside the `src` folder, create a new file called `HelloWorld.svelte`. This will be your new component.

svelte
Hello {name}!

Here’s what’s happening:
- The `

Here, we’re importing the `HelloWorld` component and rendering it inside the `main` tag. Save the file and check your browser. You should now see “Hello World!” on the screen. ?

Adding Interactivity with Svelte

Okay, let’s make things a bit more interesting. Svelte’s reactivity system is one of its standout features. It allows you to create dynamic, interactive apps with minimal effort.

Let’s modify our `HelloWorld` component to make it interactive.

Step 1: Two-Way Data Binding

We’ll add an input field that lets the user change the value of `name` in real-time.

Here’s the updated code for `HelloWorld.svelte`:

svelte
Hello {name}!

In this example:
- We’ve added an `` field that uses Svelte’s `bind:value` directive to create two-way data binding. This means that any changes to the input field will automatically update the `name` variable, and vice versa.

As you type in the input field, the heading will update in real-time. Pretty neat, right?

Handling Events in Svelte

Svelte makes it incredibly easy to handle user events like clicks, form submissions, and more. Let’s say we want to add a button that, when clicked, resets the `name` variable to its default value.

Step 1: Add Event Handlers

Here’s how you can modify the `HelloWorld.svelte` component to include a reset button:

svelte
Hello {name}!


Reset

In this code:
- We added a `resetName` function that resets the `name` variable to `'World'`.
- The `on:click` directive is used to bind the click event of the button to the `resetName` function.

Now, when you click the “Reset” button, the heading and input field will revert to their original state.

Deploying Your Svelte App

After you've built your app, the final step is to deploy it. Luckily, Svelte makes this process super straightforward.

Step 1: Build the Production Version

In your terminal, run the following command to build the optimized production version of your app:

bash
npm run build

This will create a `public` folder containing the compiled, minified files that you can deploy to any web server.

Step 2: Deploy

You can deploy your Svelte app to any hosting platform that serves static files, such as Netlify, Vercel, or GitHub Pages. Just upload the contents of the `public` folder, and you’re good to go!

Conclusion

Building web apps with Svelte and JavaScript is a breath of fresh air. Its simplicity, performance, and lack of boilerplate make it a joy to work with. Whether you’re building a simple “Hello World” app or a complex, interactive web application, Svelte has your back.

By now, you should have a basic understanding of how to set up a Svelte project, create components, add interactivity, and handle events. The best part? You did all of this with less code and a more streamlined workflow than you would with other JavaScript frameworks.

So, are you ready to jump on the Svelte bandwagon? Give it a try, and you might just find yourself reaching for Svelte in your next project instead of the usual suspects like React or Vue.