Add a Svelte Project

The code for this example is available on Github:

Example repository/nrwl/nx-recipes/tree/main/svelte

Supported Features

Because we are not using a Nx plugin for Svelte, there are a few items we'll have to configure manually. We'll have to configure our own build system. There are no pre-created Svelte-specific code generators. And we'll have to take care of updating any framework dependencies as needed.

✅ Run Tasks ✅ Cache Task Results ✅ Share Your Cache ✅ Explore the Graph ✅ Distribute Task Execution ✅ Integrate with Editors ✅ Automate Updating Nx ✅ Enforce Module Boundaries 🚫 Use Task Executors 🚫 Use Code Generators 🚫 Automate Updating Framework Dependencies

Setup workspace

Create a new Nx workspace

❯

npx create-nx-workspace@latest workspace --preset=react-monorepo --style=css --bundler=vite --nx-cloud=true --appName=acme

Add @nx/vite, svelte, and other dependencies to your workspace

❯

npm install --save-dev @nx/vite @nx/js vitest vite svelte svelte-check @sveltejs/vite-plugin-svelte

Nx 15 and lower use @nrwl/ instead of @nx/

Create the application

Before we start to create our application, let's remove the React application that was created for us.

❯

rm -rf apps/acme/src/app/*

Update your apps/acme/src/index.html to the following:

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Acme</title>
  </head>
  <body>
    <div id="app"></div>
    <script type="module" src="./src/main.ts"></script>
  </body>
</html>

Navigate to apps/acme/src/main.tsx and change it to apps/acme/src/main.ts and add the following content:

import App from './app/App.svelte';

const app = new App({
  target: document.getElementById('app'),
});

export default app;

Create a new file apps/acme/src/app/App.svelte and add the following content:

<script lang="ts">
    let count: number = 0
    const increment = () => {
      count += 1
    }
  </script>

  <button on:click={increment}>
    count is {count}
  </button>

Configure Nx to build and serve the application

Navigate to vite.config.ts update the file name to vite.config.mts and add the following content:

// Add this to your imports
import { svelte } from '@sveltejs/vite-plugin-svelte';

export default defineConfig({
  plugins: [
    //...
    svelte(),
  ],

  server: {
    port: 4200,
    host: 'localhost',
  },
});

Why use the .mts file extension?

We change vite.config.ts to vite.config.mts because '@sveltejs/vite-plugin-svelte' is an ESM only package. As a result, we need to use the .mts extension to tell Nx to use the ESM loader. See more here: ESM Package

Update your tsconfig.app.json with the following content:

/apps/acme/tsconfig.app.json
{
  "extends": "./tsconfig.json",
  "compilerOptions": {
    "moduleResolution": "node",
    "target": "esnext",
    "ignoreDeprecations": "5.0",
    "isolatedModules": true,
    "sourceMap": true,
    "types": ["svelte", "node", "vite/client"],
    "strict": false,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "checkJs": true
  },
  "include": [
    "src/**/*.d.ts",
    "src/**/*.ts",
    "src/**/*.js",
    "src/**/*.svelte",
    "vite.config.mts"
  ],
  "exclude": ["jest.config.ts", "src/**/*.spec.ts", "src/**/*.test.ts"]
}

Navigate to project.json and update it with the following content:

/apps/acme/project.json
{
  "targets": {
    "build": {
      "executor": "@nx/vite:build",
      "outputs": ["{options.outputPath}"],
      "defaultConfiguration": "production",
      "options": {
        "outputPath": "dist/apps/acme"
      },
      "configurations": {
        "development": {
          "mode": "development"
        },
        "production": {
          "mode": "production"
        }
      }
    },
    "serve": {
      "executor": "@nx/vite:dev-server",
      "defaultConfiguration": "development",
      "options": {
        "buildTarget": "acme:build"
      },
      "configurations": {
        "development": {
          "buildTarget": "acme:build:development",
          "hmr": true
        },
        "production": {
          "buildTarget": "acme:build:production",
          "hmr": false
        }
      }
    }
  }
}
Nx 15 and lower use @nrwl/ instead of @nx/

We also need to add a svelte.config.js file to the project root with the following content:

import { vitePreprocess } from '@sveltejs/vite-plugin-svelte';

export default {
  // Consult https://svelte.dev/docs#compile-time-svelte-preprocess
  // for more information about preprocessors
  preprocess: vitePreprocess(),
};

Update your package.json to include:

/package.json
{
  "type": "module"
}

Why use the type: module?

We need to add "type": "module" to our package.json file because we are using ESM only packages. See more here: ESM Package

Test it out

Build the application

❯

nx build acme

Your build artifacts should be in dist/apps/acme

Serve the application

❯

nx serve acme

Navigate to http://localhost:4200 and you should see your application.

Create a library

Instead of having our Counter directly defined in App.svelte file, let's create a library that we can import into our application.

❯

nx generate @nx/js:library --name=Counter --unitTestRunner=vitest --bundler=vite --importPath=@acme/counter

Nx 15 and lower use @nrwl/ instead of @nx/

Create the Counter component at libs/counter/src/lib/Counter.svelte and copy the contents of your apps/acme/src/App.svelte file into it.

Update your libs/counter/src/lib/index.ts to export your Counter component.

export { default as Counter } from './Counter.svelte';

Remember the default keyword

The default is import here as due to the aliasing we'll be doing later, we'll need to import the Counter component as import { Counter } from '@acme/counter'.

Update your project's /apps/acme/vite.config.mts to include the following:

export default defineConfig({
  //... other config
  resolve: {
    alias: {
      '@acme/counter': fileURLToPath(
        new URL('/libs/counter/src/index.ts', import.meta.url)
      ),
    },
  },
});

This allows the runtime to resolve the @acme/counter import to the correct location.

Finally update your apps/acme/src/App.svelte to use the counter component.

<script lang="ts">
  import { Counter } from '@acme/counter';
</script>

<Counter />

Now we can build and serve our application again.

❯

nx build acme

To generate the build artifact at dist/apps/acme.

❯

nx serve acme

To serve the application at http://localhost:4200.

Migration

Add a Svelte Project

Setup workspace

Create the application

Configure Nx to build and serve the application

Create a library

More Documentation