Type inference issue with meta function's matches argument

[tobigumo]

I'm using React Router as a...

framework

Reproduction

https://stackblitz.com/edit/github-jh2463uj?file=app%2Froutes%2Fhome.tsx

function "meta" in home.tsx

export function meta({ matches }: Route.MetaArgs) {
  // In versions prior to v7.0.1, the parent route data was inferred correctly.
  // From v7.0.2 onwards, match.id becomes unknown and type inference fails.
  const metaMatch = matches.find((match) => match && match.id === 'root');
  return [
    { title: 'New React Router App' },
    { name: 'description', content: 'Welcome to React Router!' },
  ];
}

System Info

I tested it with React Router v7.0.1, v7.0.2, and v7.1.5.


  System:
    OS: Linux 5.0 undefined
    CPU: (8) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 18.20.3 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 10.2.3 - /usr/local/bin/npm
    pnpm: 8.15.6 - /usr/local/bin/pnpm
  npmPackages:
    @react-router/dev: 7.0.2 => 7.0.2 
    @react-router/node: 7.0.2 => 7.0.2 
    @react-router/serve: 7.0.2 => 7.0.2 
    react-router: 7.0.2 => 7.0.2 
    vite: ^5.4.11 => 5.4.14

Used Package Manager

npm

Expected Behavior

In versions prior to v7.0.1, the parent route data was inferred correctly.

match is inferred as follows:

(parameter) match: {
    id: "root";
    params: {};
    pathname: string;
    meta: MetaDescriptor[];
    data: {
        path: string;
    };
    handle?: unknown;
    error?: unknown;
}

Actual Behavior

From v7.0.2 onwards, match.id becomes unknown and type inference fails.

match is inferred as follows:

(parameter) matches: [{
    id: "root";
    params: {} & {
        [key: string]: string | undefined;
    };
    pathname: string;
    meta: MetaDescriptor[];
    data: {
        path: string;
    };
    handle?: unknown;
    error?: unknown;
}, {
    id: "routes/home";
    params: {} & {
        [key: string]: string | undefined;
    };
    pathname: string;
    meta: MetaDescriptor[];
    data: {
        name: string;
    };
    handle?: unknown;
    error?: unknown;
}, ...({
    id: unknown;
    params: unknown;
    pathname: string;
    meta: MetaDescriptor[];
    data: unknown;
    handle?: unknown;
    error?: unknown;
} | undefined)[]]