Type-safe "Named Routes" Constant with Exhaustiveness Check

[rmn-kh]

I've been using TanStack Router in a large-scale project. While I love the type safety of the generated strings, my team prefers using a centralized ROUTES constant object (e.g., ROUTES.LOGIN) rather than repeating string literals throughout the app.

The challenge with a manual constants file is that it usually isn't type-safe—if you rename a file or add a new route, the constants file drifts from the actual router definition.

I implemented a TypeScript solution that utilizes RegisteredRouter["routesByPath"] to create an exhaustive check. It throws a compile-time error if my ROUTES constant is missing any route defined in the router.

I thought this might be useful for others looking for a "Named Routes" pattern, or perhaps spark a discussion on if a similar mapping could be auto-generated.

Why this is useful:

Allows usage of ROUTES.NAME intellisense throughout the app.

Prevents the constants file from becoming stale.

Leverages the existing type generation without needing a secondary codegen step.

Has anyone else implemented a similar pattern, or is there a recommended way to handle "Named Routes" aliases in TanStack Router?

// 1. Get all valid paths from the router
type AppPath = keyof RegisteredRouter["routesByPath"];

// 2. Define your constants
export const ROUTES = {
  LOGIN: "/login",
  REGISTER: "/register",
  DASHBOARD: "/dashboard",
  // ...
} as const satisfies Record<string, AppPath>;

// 3. Utility types to check coverage
type RoutesValues = (typeof ROUTES)[keyof typeof ROUTES];
type MissingRoutes = Exclude<AppPath, RoutesValues>;

// 4. The Exhaustiveness Check
// If 'MissingRoutes' is not never, this type resolves to an error object,
// causing a build failure at the const below.
type AssertAllRoutesAreDefined = MissingRoutes extends never
  ? true
  : {
      error: `Some routes are missing in ROUTES constant: ${MissingRoutes}`;
    };

// This will error if you add a new file but forget to add it to ROUTES
export const _exhaustiveCheck: AssertAllRoutesAreDefined = true; ```