{ lib, ... }: let userPrefValue = pref: builtins.toJSON ( if lib.isBool pref || lib.isInt pref || lib.isString pref then pref else builtins.toJSON pref ); in { mkConfig = prefs: lib.concatStrings ( lib.mapAttrsToList (name: value: '' user_pref("${name}", ${userPrefValue value}); '') prefs ); }