gem-hunter

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

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;

NOTE A default import of the plugin using import dts from "rollup-plugin-dts"; is still supported for existing implementations of this package. However, a named import is suggested to avoid the error [!] TypeError: dts is not a function¹² in certain rollup config file implementations.

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.

plugins: [dts({
  // Enable detailed sourcemaps for Go-to-Definition support.
  // When true: loads .d.ts.map files and captures TypeScript's declarationMap
  // for .ts inputs, enabling navigation to original source files.
  // NOTE: Also requires `output.sourcemap: true` in your Rollup config.
  sourcemap: true,

  // Path to tsconfig.json (default: finds nearest tsconfig.json)
  tsconfig: "./tsconfig.json",

  // TypeScript compiler options (e.g., for path mapping)
  compilerOptions: { baseUrl: ".", paths: { "~/*": ["src/*"] } },

  // Don't auto-externalize node_modules (default: false)
  respectExternal: true,

  // Bundle types from specific external packages (default: [])
  includeExternal: ["some-package"],
})]

TypeScript 7.0 (the native compiler) does not ship a compiler API, which this plugin relies on. When your project uses typescript@7, additionally install the official compatibility package that provides the TypeScript 6 API:

$ npm install --save-dev @typescript/typescript6

The plugin uses the API from your typescript package when it provides one (TypeScript 4.5 – 6.x), and automatically falls back to @typescript/typescript6 otherwise. Declaration files are parsed and emitted with the TypeScript 6 language behavior in that case, which is identical for declaration output. Once TypeScript 7.1+ ships its new compiler API, a future release will support it directly.

Note that this plugin's public types reference the typescript package (e.g., ts.CompilerOptions), which typescript@7 does not currently provide. If you type-check a file that imports rollup-plugin-dts (such as rollup.config.ts) with TypeScript 7, enable skipLibCheck to avoid a spurious error inside the plugin's declaration file.

This project is in maintenance mode. That means there will be no more active feature development. There will still be occasional releases to maintain compatibility with future TypeScript releases. Pull Requests are always welcome, however reaction time on both Issues and PRs can be slow.

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.

When a bundled entry exposes a type that originally came from a private shared chunk, downstream tsc --declaration runs can fail with TS2742.

This is part of a broader TypeScript declaration portability problem. For upstream context, see ./*.d.ts required in exports to avoid ...not portable... for one shape of the bug, and Elaborate on non-portable types for the related error-message discussion.

This plugin will try to rewrite that path through an entry that already re-exports the type publicly. That keeps the existing public API and can make the bundled declarations portable for downstream consumers.

The plugin does not invent new public exports. If no public entry re-exports the shared type, the bundled package can still trigger TS2742. In that case, the plugin emits a warning and the package should re-export the type from a public entry explicitly.

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.

• API Extractor
• dts-bundle-generator
• rollup-plugin-ts
• tsc-prog

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

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

Footnotes

1. StackOverflow thread of issue ↩

2. Github issue ↩