rollup-plugin-dts

This is a plugin that lets you roll-up your .d.ts definition files.

Usage

Install the package from npm:

$ npm install --save-dev rollup-plugin-dts

Add it to your rollup.config.js:

import dts from "rollup-plugin-dts";

const config = [
  // …
  {
    input: "./my-input/index.d.ts",
    output: [{ file: "dist/my-library.d.ts", format: "es" }],
    plugins: [dts()],
  },
];

export default config;

And then instruct typescript where to find your definitions inside your package.json:

  "types": "dist/my-library.d.ts",

NOTE that the plugin will automatically mark any external library (@types for example) as external, so those will be excluded from bundling.

What to expect

While this plugin is fairly complete, it does not support all imaginable use-cases. In particular, the plugin works best with already existing .d.ts files generated by the typescript compiler from idiomatic code.

Working with .ts(x) or even .js(x) (when setting allowJs: true) does work, but is not recommended.

The plugin does its own import resolution through the typescript compiler, and usage together with other resolution plugins, such as node-resolve can lead to errors and is not recommended.

All external dependencies from node_modules are automatically excluded from bundling. This can be overridden using the respectExternal setting, but it is generally not recommended. While rollup of external @types generally works, it is not recommended.

Why?

Well, ideally TypeScript should just do all this itself, and it even has a proposal to do that. But there hasn’t been any progress in ~3 years.

Some projects, like rollup itself go the route of completely separating their public interfaces in a separate file.

Alternatives

See some discussions about some of these projects and their tradeoffs.

How does it work

License

The code is licensed under the copyleft LGPL-3.0. I have no intention to license this under any non-copyleft license.