Nix / NixOS : Import all files from current directory

default.nix

{...}: {
  # imports by full path without copying to /nix/store
  imports = builtins.map (n: toString ./. + "/${n}") (builtins.attrNames (builtins.removeAttrs (builtins.readDir ./.) [(builtins.unsafeGetAttrPos "_" {_ = null;}).file]));
  
  # copies all files from the current directory to /nix/store and imports from /nix/store
  # imports = builtins.map (n: "${./.}/${n}") (builtins.attrNames (builtins.removeAttrs (builtins.readDir ./.) [(builtins.unsafeGetAttrPos "_" {_ = null;}).file]));
}

a more advanced implementation of this thing
https://github.com/yunfachi/nixpkgs-yunfachi/blob/master/lib/umport.nix

{umport, ...}: {
  imports = umport {path = ./.;};
}

{umport, ...}: {
  imports = umport {
    path = ./.; # a required parameter that must be specified in the current file
    include = [../../bar.nix]; # default []
    exclude = [./foo.nix]; # defaults to [], but always excludes the current file
    copyToStore = true; # default false
  };
}