Meet dtsx

If you publish TypeScript libraries, you know the pain: generating .d.ts files with tsc is the slowest part of the build. dtsx replaces that step with a fast, focused declaration emitter.

The isolated declarations bet

TypeScript's isolatedDeclarations mode requires you to annotate your public API explicitly, so declarations can be emitted from each file independently, without whole-program type checking. That trade unlocks enormous speed: no cross-file inference, no waiting on the type checker.

dtsx leans into this. Annotate your exports, and it emits declarations in a fraction of the time a full tsc --emitDeclarationOnly run takes.

Usage

bunx dtsx

Or as a library, and as bun-plugin-dtsx inside Bun's bundler, so your bun build produces bundles and declarations in one pass:

import dts from 'bun-plugin-dtsx'

await Bun.build({
  entrypoints: ['src/index.ts'],
  outdir: 'dist',
  plugins: [dts()],
})

Every package in the stacksjs ecosystem ships its types through dtsx, which is a good stress test: hundreds of entry points, complex generics, and re-exports across workspaces.

Grab it at github.com/stacksjs/dtsx.