nixos-config/modules/nixos/_private/state/paths.nix

{ lib, ... }:

{
  options.state = let
    directoriesSubmodule = { lib, ... }: {
      options = {
        paths = lib.mkOption {
          type = with lib.types; attrsOf (either path (listOf str));
          description = ''
            A set of directories to share its value to various parts of the
            system.
          '';
          default = { };
          example = {
            cacheDir = "/var/cache";
            ignoreDirectories = [ "/var/log" ];
            ignoreFiles = [ "node_modules" ".gitignore" ".bak" ];
          };
        };
      };
    };
  in lib.mkOption { type = lib.types.submodule directoriesSubmodule; };
}