svelte/site

sapper-template-rollup

A version of the default Sapper template that uses Rollup instead of webpack. To clone it and get started:

npx degit sveltejs/sapper-template#rollup my-app
cd my-app
npm install # or yarn!
npm run dev

Open up localhost:3000 and start clicking around.

Consult sapper.svelte.technology for help getting started.

Click here for the webpack version of this template

Structure

Sapper expects to find three directories in the root of your project — app, assets and routes.

app

The app directory contains the entry points for your app — client.js, server.js and (optionally) a service-worker.js — along with a template.html file.

assets

The assets directory contains any static assets that should be available. These are served using sirv.

In your service-worker.js file, you can import these as assets from the generated manifest...

import { assets } from './manifest/service-worker.js';

...so that you can cache them (though you can choose not to, for example if you don't want to cache very large files).

routes

This is the heart of your Sapper app. There are two kinds of routes — pages, and server routes.

Pages are Svelte components written in .html files. When a user first visits the application, they will be served a server-rendered version of the route in question, plus some JavaScript that 'hydrates' the page and initialises a client-side router. From that point forward, navigating to other pages is handled entirely on the client for a fast, app-like feel. (Sapper will preload and cache the code for these subsequent pages, so that navigation is instantaneous.)

Server routes are modules written in .js files, that export functions corresponding to HTTP methods. Each function receives Express request and response objects as arguments, plus a next function. This is useful for creating a JSON API, for example.

There are three simple rules for naming the files that define your routes:

• A file called routes/about.html corresponds to the /about route. A file called routes/blog/[slug].html corresponds to the /blog/:slug route, in which case params.slug is available to the route
• The file routes/index.html (or routes/index.js) corresponds to the root of your app. routes/about/index.html is treated the same as routes/about.html.
• Files and directories with a leading underscore do not create routes. This allows you to colocate helper modules and components with the routes that depend on them — for example you could have a file called routes/_helpers/datetime.js and it would not create a /_helpers/datetime route

Rollup config

Sapper uses Rollup to provide code-splitting and dynamic imports, as well as compiling your Svelte components. As long as you don't do anything daft, you can edit the configuration files to add whatever plugins you'd like.

Production mode and deployment

To start a production version of your app, run npm run build && npm start.

You can deploy your application to any environment that supports Node 8 or above. As an example, to deploy to Now, run these commands:

npm install -g now
now

Bugs and feedback

Sapper is in early development, and may have the odd rough edge here and there. Please be vocal over on the Sapper issue tracker.