Setting up a SvelteKit project with Storybook

This will walk you through the steps to set up a new SvelteKit project with StorybookJS. It will also configure Storybook to use ViteJS. Using Vite gets the local storybook server up and running around ~50x faster.

Note: I’ve opted to use TypeScript in this guide, but it works just as well for JavaScript. As of April 2022, Storybook supports svelte components implemented in TS, but does not support stories written in TypeScript yet.

Initialize a SvelteKit project:

npm init svelte@next my-sveltekit-app

Confirm that it can install create-svelte@next then continue to the SvelteKit config options. My preferred config is as follows:

Option Selection
Which Svelte app template? Skeleton project
Add type checking? TypeScript
Add ESLint for code linting? Yes
Add Prettier for code formatting? Yes
Add Playwright for browser testing? No

With SvelteKit configured, we can start setting up StorybookJS:

cd my-sveltekit-app
npx sb init --builder @storybook/builder-vite

The automated StorybookJS configuration tool will run and set things up for a Svelte project. It’ll ask you if you want to set up the storybook linter plugin:

Option Selection
Do you want to run the ‘eslintPlugin’ fix on your project? Yes

Once the setup is done, there are a couple manual config steps we need to go through.

First we need to tell Storybook to use CommonJS. Create the file .storybook/package.json and add the following to it:

// .storybook/package.json
{
  "type": "commonjs"
}

Then we need to remove Storybook’s preprocessing config and tell ViteJS how to find and preprocess our svelte files:

  1. Remove "preprocess": require("../svelte.config.js").preprocess
  2. Import the svelte preprocessor: const preprocess = require('svelte-preprocess');
  3. Import the path package to help with include paths: const path = require('path');
  4. Set the ViteJS config to use the svelte preprocessor and include paths (see the async viteFinal(config, {configType}) {...} below)

The final .storybook/main.js file should look like this:

// .storybook/main.js
const preprocess = require('svelte-preprocess');
const path = require('path');
module.exports = {
  "stories": [
    "../src/**/*.stories.mdx",
    "../src/**/*.stories.@(js|jsx|ts|tsx|svelte)"
  ],
  "addons": [
    "@storybook/addon-links",
    "@storybook/addon-essentials",
    "@storybook/addon-svelte-csf"
  ],
  "framework": "@storybook/svelte",
  "core": {
    "builder": "@storybook/builder-vite"
  },
  async viteFinal(config, { configType }) {
    config.preprocess = preprocess({});
    config.resolve.alias = {
	  // alias: path
	  $components: path.resolve('./src/components'),
	  $routes: path.resolve('./src/routes'),
	  $lib: path.resolve('./src/lib'),
	  // The $styles alias is used to setup tailwindcss 
	  $styles: path.resolve('./src/styles'),
	};
    return config;
  },
}

Note: if you have different include path aliases, you’ll want to make sure that the ones in .storybook/main.js match your svelte.config.js and tsconfig.json aliases

Voila! You should be all set.

Bonus: Tailwindcss support

If you also want to use tailwindcss with both SvelteJS/SvelteKit and StorybookJS, that config has a couple of gotchas as well. Here’s the steps to get it up and running.

First, install tailwindcss in your SvelteKit project (per the official tailwind docs):

npm install -D tailwindcss postcss autoprefixer
npx tailwindcss init tailwind.config.cjs -p
mv postcss.config.js postcss.config.cjs

Then update the tailwind.config.cjs so it knows where to find your components:

// tailwind.config.cjs
module.exports = {
  content: ['./src/**/*.{html,js,svelte,ts}'],
  theme: {
    extend: {}
  },
  plugins: []
};

Create a src/styles/tailwind.css file that sets up tailwindcss for your components:

@tailwind base;
@tailwind components;
@tailwind utilities;

Finally, create a src/routes/__layout.svelte file that includes tailwindcss for your sveltekit project:

<script>
  import "$styles/tailwind.css";
</script>

<slot />

At this point tailwindcss should be working in your SvelteKit project. It won’t be working in the StorybookJS view of your components though; storybook still needs to be configured to use tailwindcss. To do that add the following line to the top of .storybook/preview.js:

// .storybook/preview.js
import '$styles/tailwind.css';

// No need to touch the rest of it, which for me looks like this:
export const parameters = {
  actions: { argTypesRegex: "^on[A-Z].*" },
  controls: {
    matchers: {
      color: /(background|color)$/i,
      date: /Date$/,
    },
  },
}

!Note: the .storybook/main.js file needs to have the alias $styles: path.resolve('./src/styles') set in vite’s config.resolve.alias object for the import '$styles/tailwind.css' to work.

That’s it! You should have the following correctly set up now:

  • SvelteKit using TypeScript, styleable with tailwindcss, all using ViteJS
  • A complementary StorybookJS also using ViteJS and tailwindcss for your TypeScript components.

Sadly as of now (May 2022) your stories still need to be authored in JavaScript.