# @astrojs/svelte ๐Ÿงก This **[Astro integration][astro-integration]** enables server-side rendering and client-side hydration for your [Svelte](https://svelte.dev/) components. ## Installation There are two ways to add integrations to your project. Let's try the most convenient option first! ### `astro add` command Astro includes a CLI tool for adding first party integrations: `astro add`. This command will: 1. (Optionally) Install all necessary dependencies and peer dependencies 2. (Also optionally) Update your `astro.config.*` file to apply this integration To install `@astrojs/svelte`, run the following from your project directory and follow the prompts: ```sh # Using NPM npx astro add svelte # Using Yarn yarn astro add svelte # Using PNPM pnpm astro add svelte ``` If you run into any issues, [feel free to report them to us on GitHub](https://github.com/withastro/astro/issues) and try the manual installation steps below. ### Install dependencies manually First, install the `@astrojs/svelte` integration like so: ```sh npm install @astrojs/svelte ``` Most package managers will install associated peer dependencies as well. Still, if you see a "Cannot find package 'svelte'" (or similar) warning when you start up Astro, you'll need to install Svelte: ```sh npm install svelte ``` Now, apply this integration to your `astro.config.*` file using the `integrations` property: __`astro.config.mjs`__ ```js import svelte from '@astrojs/svelte'; export default { // ... integrations: [svelte()], } ``` ## Getting started To use your first Svelte component in Astro, head to our [UI framework documentation][astro-ui-frameworks]. You'll explore: - ๐Ÿ“ฆ how framework components are loaded, - ๐Ÿ’ง client-side hydration options, and - ๐Ÿค opportunities to mix and nest frameworks together ## Troubleshooting For help, check out the `#support` channel on [Discord](https://astro.build/chat). Our friendly Support Squad members are here to help! You can also check our [Astro Integration Documentation][astro-integration] for more on integrations. ## Contributing This package is maintained by Astro's Core team. You're welcome to submit an issue or PR! [astro-integration]: https://docs.astro.build/en/guides/integrations-guide/ [astro-ui-frameworks]: https://docs.astro.build/en/core-concepts/framework-components/#using-framework-components ## Options This integration is powered by `@sveltejs/vite-plugin-svelte`. To customize the Svelte compiler, options can be provided to the integration. See the `@sveltejs/vite-plugin-svelte` [docs](https://github.com/sveltejs/vite-plugin-svelte/blob/HEAD/docs/config.md) for more details. ### Default options A few of the default options passed to the Svelte compiler are required to build properly for Astro and cannot be overridden. ```js const defaultOptions = { emitCss: true, compilerOptions: { dev: isDev, hydratable: true }, preprocess: vitePreprocess() }; ``` The `emitCss`, `compilerOptions.dev`, and `compilerOptions.hydratable` cannot be overridden. Providing your own `preprocess` options **will** override the defaults - make sure to enable the preprocessor flags needed for your project. For example, ```js // astro.config.js import svelte from '@astrojs/svelte'; export default { integrations: [svelte({ preprocess: [] })], }; ``` and ```js // svelte.config.js export default { preprocess: [], }; ``` Will override the default `preprocess` option. You can read the [`vitePreprocess` docs](https://github.com/sveltejs/vite-plugin-svelte/blob/HEAD/docs/preprocess.md) for more information of how it works. ## Intellisense for TypeScript If you're using a preprocessor like TypeScript or SCSS in your Svelte files, you can create a `svelte.config.js` file with: ```js import { vitePreprocess } from '@astrojs/svelte'; export default { preprocess: vitePreprocess(), }; ``` So the Svelte IDE extension can correctly parse the Svelte files. This config file is added by default when you run `astro add svelte`.