modules/nixos/multimedia/web/firefox/preferences.nix

@@ -1,12 +1,21 @@
 let
+  prefToString = value:
+    if builtins.isBool value then
+      if value then "true" else "false"
+    else if (builtins.isInt value) || (builtins.isNull value) then
+      builtins.toString value
+    else if builtins.isString value then
+      value
+    else
+      builtins.throw
+        "Pref expected one of (Bool, String, Int, Null) got instead ${builtins.typeOf value}";
+
   mkPrefs = prefs: builtins.concatStringsSep 
     "\n"
     (builtins.attrValues
       (builtins.mapAttrs
-        (n: v: ''user_pref("${n}", "${v}");'') prefs));
+        (n: v: ''user_pref("${n}", "${(prefToString v)}");'') prefs));
 in 
   mkPrefs {
-    prefs = {
+    "browser.urlbar.suggest.topsites" = "false";
-      "browser.urlbar.suggest.topsites" = false;
-    };
   }