TypeScript type declarations shipped

Shipping an npm package without TypeScript declarations means every consumer is flying blind. IDEs show any for all imports, type errors go unreported until runtime, and documentation-on-hover disappears entirely. ISO 25010 analysability collapses — developers must clone your repo just to understand your API surface. For TypeScript projects (now the majority of serious npm consumers), a package without .d.ts files is effectively unusable without manual declare module workarounds.

Enable declaration generation in tsconfig.json, configure your build tool to emit .d.ts files, and reference them in package.json.

// tsconfig.json
{
  "compilerOptions": {
    "declaration": true,
    "declarationMap": true,
    "outDir": "dist"
  }
}

// tsup.config.ts
import { defineConfig } from 'tsup'
export default defineConfig({ entry: ['src/index.ts'], format: ['esm', 'cjs'], dts: true })

// package.json
{
  "types": "./dist/index.d.ts",
  "exports": { ".": { "types": "./dist/index.d.ts" } }
}

Verify declarations exist after build: ls dist/*.d.ts. Declarations auto-typed as any do not satisfy this check.