How to Build SPAs With SvelteKit and SSR

Single Page Applications (SPAs) have changed the way modern web applications are built by providing a seamless user experience. SvelteKit, a powerful framework for building SPAs with Svelte, offers built-in support for Server-Side Rendering (SSR). This guide will walk you through how to build SPAs using SvelteKit with an emphasis on SSR.

Setting Up Your SvelteKit Project

The first step in building a SPA with SvelteKit is to set up your development environment. If you haven’t already, ensure you have Node.js installed on your machine. To create a new SvelteKit project, run the following command in your terminal:

npm init svelte@next my-svelte-app

Next, navigate into your new project directory:

cd my-svelte-app

Once inside your project folder, install the necessary dependencies:

npm install

Understanding the File Structure

SvelteKit employs a file-based routing system. Your project structure will typically look like this:

src/
 ├── routes/
 │   ├── index.svelte
 │   ├── about.svelte
 │   └── [slug].svelte
 ├── lib/
 ├── app.html
 └── global.css

The files within the routes directory correspond to different pages of your SPA. The index.svelte file represents the home page, while other `.svelte` files correspond to different routes in your application.

Implementing Server-Side Rendering (SSR)

SvelteKit provides SSR out of the box, which allows you to pre-render your pages on the server before they are sent to the client. To enable SSR for a specific route, you can use the load function within your route files.

Here’s an example of how to fetch data for an about page using SSR:

// src/routes/about.svelte


{data.title}
{data.content}

In the above snippet, the load function fetches data from an external API when the server renders the page. This data is passed as props to the component, ensuring that it's available when the page loads.

Building Your SPA's Components

A SPA often consists of reusable components. You can create them within the src/lib directory. Here’s how to create a simple button component:

// src/lib/Button.svelte

You can then import and use this component in any of your routes:

// src/routes/index.svelte

Welcome to My SvelteKit SPA

Deploying Your SvelteKit SPA

Once your application is ready, it’s time to deploy. SvelteKit supports various deployment targets. For static hosting, you can build your project using:

npm run build

This will generate static files that can be served directly from any static hosting service like Vercel, Netlify, or GitHub Pages.

Conclusion

Building SPAs with SvelteKit and SSR provides a modern development experience that enhances performance and user satisfaction. By utilizing Svelte's reactivity and SvelteKit's routing and SSR capabilities, you can create highly interactive and efficient web applications.

Start experimenting with SvelteKit today to unlock the full potential of SPAs in your projects.

How to Build SPAs With SvelteKit and SSR