this type quite smell for me as I expect that hidden network contain more entries...why WifiNetwork cannot be used? or maybe instead of const variable method that do that simple check for hidden value on common WifiNetwork type can be used?

Let me revisit this and see how we can improve it. I think yesterday we added the hidden attribute to WifiNetwork type, which was not the case before and probably the reason why this weird, ad-hoc type is here.

Good catch!

Ok, I see now. WifiNetwork is an AccessPoint plus WifiNetworkStatus plus other optional values like hidden. So, HIDDEN_NETWORK cannot be a WifiNetwork sinde it does belong to none access point. A bit lost here, so I prefere to wait until @teclator can have a look.

so selected wifi can be empty? it looks kind of strange. I expect that at least ssid is mandatory.

It's not that strange. You can connect to a hidden Wi-Fi network.

It is strange for me as hidden network has SSID. The difference is that AP does not broadcast that SSID, so it is not visible when you scan list of available network. But to be able to connect to it, you need to know SSID. Just try it with your NM applet, when you want to connect to hidden network you have to provide its name

Yeah, I know how hidden network works :) But the problem is that this is a "UI query" for keeping which network is/was selected by the user in order to show the proper information about it: the connection form or its configuration/state and actions.

But the user could select a "hidden network", for which the UI does not know the SSID in advance. That's why the ssid here is optional. Maybe a matter of naming or a matter or typing improvement (I'm just landing in the typed languages world :P)

How would you improve it?

at least document that info in the type as it is confusing for reader. So mention that for hidden network ssid is not known in advance. I am not sure if you can have something in ts like that hidden is true or ssid is specified.

I am not sure if you can have something in ts like that hidden is true or ssid is specified.

Interesting point. I'm going to see if that it's possible. Thanks a ton!

Argh! Actually is a bit more tricky than I though because I forgot to mention a small detail in previous explanations: we're updating the information in the query in a moment in which we don't know the ssid but only that the authentication failed. So, we assumed that authentication failed for the selected connection. See https://github.com/openSUSE/agama/pull/1519/files#diff-f1b1879261cce23d74bb1716c65fbbcb487ee658acf074133fc6d6def7288736R223-R263

So, to make it work without TypeScript complaints the changes would be something like

diff --git a/web/src/queries/network.ts b/web/src/queries/network.ts
index 00754d6d..d8fecc7a 100644
--- a/web/src/queries/network.ts
+++ b/web/src/queries/network.ts
@@ -193,16 +193,25 @@ const useSelectedWifi = (): { ssid?: string; needsAuth?: boolean; hidden?: boole
 };
 
 const useSelectedWifiChange = () => {
-  type SelectedWifi = {
-    ssid?: string;
-    hidden?: boolean;
-    needsAuth?: boolean;
+  type VisibleWifi = {
+    ssid: string;
+    hidden?: false | never;
   };
 
+  type HiddenWifi = {
+    ssid?: never;
+    hidden: true;
+  };
+
+  type KnownWifi = VisibleWifi & { needsAuth?: boolean };
+
+  type SelectedWifi = KnownWifi | HiddenWifi;
+
   const queryClient = useQueryClient();
 
   const mutation = useMutation({
-    mutationFn: async (data: SelectedWifi): Promise<SelectedWifi> => Promise.resolve(data),
+    mutationFn: async (data: Partial<SelectedWifi>): Promise<Partial<SelectedWifi>> =>
+      Promise.resolve(data),
     onSuccess: (data: SelectedWifi) => {
       queryClient.setQueryData(["wifi", "selected"], (prev: SelectedWifi) => ({
         ssid: prev.ssid,

On one hand, from the typing POV would be more clear that a hidden wifi is unknown until the user enters the ssid and became it in a KnownWifi. On the other hand... although safer and robust code looks a bit complicated. What do you think?