Error is gone. Here’s the full explanation of everything at play:

Summary: TypeScript + package.json exports in monorepo

Why the error occurred

Your tsconfig.base.json has composite: true, which implies all source files must be under rootDir (defaults to the tsconfig’s directory). When TypeScript resolves @package/ui/Navigation via the exports field → ./src/Navigation/index.ts, that file lives in package/ui/, which is outside package/app/‘s rootDir. Hence the error.

Additionally, include: ["../ui/**/*.ts"] was directly pulling ui source into app’s program — a double violation.

How TypeScript resolves package.json exports

With moduleResolution: "Bundler" (your base config), TypeScript fully supports the exports field:

  1. import {RouterLink} from '@package/ui/Navigation'
  2. TS finds @package/ui → reads package.json
  3. Matches exports["./Navigation"] → uses types condition → ./src/Navigation/index.ts
  4. Resolution succeeds

The issue was never about exports compatibility — it was about composite‘s rootDir enforcement.

What was changed

package/app/tsconfig.json:

  • Overrode composite: false, declaration: false, declarationMap: false, emitDeclarationOnly: false — app is a leaf Vite application, not a library, so it doesn’t need these
  • Removed "../ui/**/*.ts", "../ui/**/*.tsx" from include — app should only compile its own source; cross-package types come through exports resolution
  • Removed outDir since app doesn’t emit anything (Vite handles bundling)

Root tsconfig.json:

  • Removed app from references — without composite, it can’t participate in tsc -b

The pattern for extensionless cross-package imports

Your current package/ui/package.json exports setup is correct for this:

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"./*": {
  "types": "./src/*",
  "import": "./src/*"
},
"./Navigation": {
  "types": "./src/Navigation/index.ts",
  "import": "./src/Navigation/index.ts"
}
  • Wildcard ./* — handles extensionless file imports like @package/ui/SomeFile
  • Explicit ./Navigation — needed for directory-based exports (where the actual file is index.ts inside a folder), because the wildcard won’t automatically append /index.ts

The rule: for any directory with an index.ts, add an explicit exports entry. Wildcards only work for direct file-to-file mapping.