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How to Setup a Sapper Project

11/16/2020 - 4 min read


You should know basic HTML, CSS, and JavaScript. No prior knowledge of Svelte or Sapper.js is needed. You'll also want to make sure you have npm installed. If you don't, here's how install it on Mac or Windows.

So You want to learn Sapper

Sapper.js and Svelte are still quite niche, so most of you reading this mostly likely stumbled across this via a specific Google (or DuckDuckGo 🦆) search or are doing your very best to be a JavaScript hipster. So I won't spend too much time elaborating on the excellencies of the Svelte ecosystem.

What is Sapper

Sapper is what some would call a 'meta' or 'application' framework, a framework to use on top of a web/JavaScript framework. In this case, Sapper is used on top of Svelte. Another example that might clear things up is the use case of developing a React project with Next.js. Speaking of Next.js, it's a distant cousin of Sapper, and I think it's safe to say even a primary source of inspiration.

Some of the primary benefits of Sapper include advanced routing, server-side rendering (SSR), and code-splitting. To put it in the words of the Sapper team,

Sapper does all the boring stuff for you so that you can get on with the creative part.

A Word of Warning Before Going Further

Sapper will be deprecated, so don't use it for production. It's still ok to use for a personal project. Sapper will ultimately be replaced by a new Svelte project that'll include many Sapper features by default. Per Rich Harris, you should be able to easily migrate your Sapper apps to this new framework.

To learn more, you can watch the official announcement from Rich.

Time to Get Started!

Install NPX

Check to see if you need to install npx - On Windows, might need to manually install - Otherwise, it comes bundled with Node 5.2+

Install and Run Degit

Install degit, a package for quick project scaffolding, with npx install degit

Now, run npx degit "sveltejs/sapper-template#rollup" my-app. This commands create a project template similar to Create React App, with a default folder structure, example files, and pre-configured Rollup or Webpack settings. It goes without saying you can replace most of the files - these are here to quickly get you off the ground and give you a mental framework for how Sapper operates.

Open Your Project

Open your file in VS Code or run cd my-app in your terminal. Then, run npm install, followed by npm run dev. Your app should be running locally now, so go to localhost:3000 to view it. You should see this as your home view:

sapper home view

Make Your First Route

One of the best parts of Sapper, in my opinion, is the way routing works. Want to create a new top-level route like localhost:3000/hello_world? All you need to do is create a new file called hello_word.svelte in src/routes.

Once you've created the file, maybe add a header so you can identify the page when you land on it. In Svelte/Sapper, you don't need to use any boilerplate to get your app to recognize what's HTML, styles, or script. Throw on an HTML tag, and it'll work!

<h1>Hello World</h1>

Ok, so now we need to add the new route to the nav bar. Head over to src/components/Nav.svelte. On line 59, or under the last existing <li> element, add your new route.

        aria-current="{segment === 'hello_world' ?'page' : undefined}"
        hello world

Take a look at your nav bar and you should your new route as an option. Click on it and you should be greeted with:

sapper route view

Final Thoughts

And there you go! You've not only got your first Sapper project up and running, you now know how to create a new route.

Happy building!