Nix has an [attribute selection operator `. or`](https://nixos.org/manual/nix/stable/language/operators#attribute-selection) which is sufficient for such queries, as long as the number of attributes is static. For example:
Nix has an [attribute selection operator `.`](https://nixos.org/manual/nix/stable/language/operators#attribute-selection) which is sufficient for such queries, as long as the number of attributes is static. For example: