@ogygia/tsdown-plugin-svelte

Options

Every option of svelte(), with its default, and how to set root in a monorepo.

On this page

preprocess
dts and tsconfig
In a monorepo

svelte() takes one options object, and every key is optional:

svelte({
  root: process.cwd(),
  src: 'src',
  out: 'dist',
  preprocess: vitePreprocess({ script: true }),
  dts: true,
  tsconfig: 'tsconfig.json'
});

Option	Default	What it does
`root`	`process.cwd()`	The package root that `src`, `out` and `tsconfig` are relative to.
`src`	`'src'`	Where your components and `.css` files live.
`out`	`'dist'`	Where they are written. Match tsdown’s `outDir`.
`preprocess`	`vitePreprocess({ script: true })`	Svelte preprocessors for the script and styles (one or a list).
`dts`	`true`	Write a `.svelte.d.ts` beside each component. Needs `svelte2tsx` and `typescript`.
`tsconfig`	`'tsconfig.json'`	The tsconfig the component types are generated with.

preprocess

The default is vitePreprocess({ script: true }) from @sveltejs/vite-plugin-svelte, which turns <script lang="ts"> into JS. Pass your own preprocessors to add others (for example a CSS preprocessor), or to avoid the @sveltejs/vite-plugin-svelte dependency. Without it installed and without preprocess, the build stops with a message that says so.

dts and tsconfig

The component types are generated with your tsconfig.json, extended with isolatedDeclarations turned off: svelte2tsx’s generated component code never carries the annotations that option demands, so a library that turns it on for its .ts files would otherwise get no component types. Your .ts declarations are still tsdown’s, built with your config as it is.

In a monorepo

When tsdown runs from another folder (a workspace root, a shared build script), set root to the package’s own folder:

import { fileURLToPath } from 'node:url';

svelte({ root: fileURLToPath(new URL('.', import.meta.url)) });