Svelte Support

tsdown supports building Svelte component libraries by integrating rollup-plugin-svelte. This setup compiles .svelte components and bundles them alongside your TypeScript sources.

Quick Start

For the fastest way to get started, use the Svelte component starter template. This starter project comes pre-configured for Svelte library development.

npx create-tsdown@latest -t svelte

Minimal Example

Configure tsdown for a Svelte library with the following tsdown.config.ts:

tsdown.config.ts

import svelte from 'rollup-plugin-svelte'
import { sveltePreprocess } from 'svelte-preprocess'
import { defineConfig } from 'tsdown'

export default defineConfig({
  entry: ['./src/index.ts'],
  platform: 'neutral',
  plugins: [svelte({ preprocess: sveltePreprocess() })],
})

Install the required dependencies:

npm

npm install -D rollup-plugin-svelte svelte svelte-preprocess

pnpm

pnpm add -D rollup-plugin-svelte svelte svelte-preprocess

yarn

yarn add -D rollup-plugin-svelte svelte svelte-preprocess

bun

bun add -D rollup-plugin-svelte svelte svelte-preprocess

How It Works

• rollup-plugin-svelte compiles .svelte single-file components.
• tsdown bundles the compiled output with your TypeScript sources.

INFO

Generating .d.ts for Svelte components typically requires integrating svelte2tsx. We recommend using the dedicated Svelte template, which includes an emission step based on svelte2tsx to generate declarations after bundling.