Building a TypeScript Library

The Lib plugin configures Vite to build an ESM TypeScript library with sensible defaults.

Basic setup

// vite.config.ts
import { defineConfig } from "vite"
import { Lib } from "marmotte/vite/lib"

export default defineConfig({
  plugins: Lib(),
})

This single call wires up:

• ESM-only output (formats: ["es"]) with source maps and no minification.
• Preserved modules — the output mirrors your source tree, which is ideal for tree-shaking by consumers.
• TypeScript declarations (.d.ts + .d.ts.map) via vite-plugin-dts. The build fails on type errors.
• Node externals — everything in dependencies and peerDependencies is excluded from the bundle.
• VitePress docs embedded in the dev server (see Documentation).
• @ alias pointing to your src/ directory.
• VITE_PACKAGE_NAME / VITE_PACKAGE_VERSION env vars injected from package.json.

Entry points

By default, src/index.ts is the single entry point. Use the entries option to expose multiple modules:

Lib({
  // include every .ts file that isn't a declaration, test, or test-type file
  entries: /(?<!\.d)(?<!\.test)(?<!\.test-d)\.ts$/,
})

entries accepts a RegExp or a (absolutePath: string) => boolean predicate. Files are discovered by recursively walking src/. Entry names in the Rollup output map match the relative path without extension.

You can also define entries manually in vite.config.ts (build.lib.entry) alongside or instead of the entries filter.

Options

Lib({
  // Entry filter (see above)
  entries: /\.ts$/,

  // Pass-through to vite-plugin-dts
  dts: {
    tsconfigPath: "./tsconfig.lib.json",
  },

  // Pass-through to rollup-plugin-node-externals
  externals: {
    devDeps: false, // don't externalise devDependencies
  },

  // Disable the embedded docs server
  docs: false,
})

See the API reference for the full option types.

Low-level: LibConfig

LibConfig is the inner plugin that only handles entry resolution and build settings. Use it if you want to compose your own plugin stack without the DTS generator, externals, or docs:

import { LibConfig } from "marmotte/vite/lib"

export default defineConfig({
  plugins: [
    LibConfig({ entries: /\.ts$/ }),
    // add your own plugins
  ],
})

Typical package.json

For a library built with Lib() the exports map should look like:

{
  "type": "module",
  "exports": {
    ".": {
      "types": "./dist/index.d.ts",
      "import": "./dist/index.js"
    }
  }
}

For multi-entry builds produced by the entries filter:

{
  "exports": {
    "./*": {
      "types": "./dist/*.d.ts",
      "import": "./dist/*.js"
    }
  }
}