setup: report panic errors to user

many issues occur with setup, all this does is tell the user something
bad happened and to check the logs. Might help with solving issues.
Also fixed some now invalid typescript.

ts/setup.ts

@@ -1,4 +1,4 @@
-import { _get, _post, toggleLoader } from "./modules/common.js";
+import { _get, _post, toggleLoader, notificationBox } from "./modules/common.js";
 import { lang, LangFile, loadLangSelector } from "./modules/lang.js";
 
 interface sWindow extends Window {
@@ -8,6 +8,10 @@ interface sWindow extends Window {
 declare var window: sWindow;
 window.URLBase = "";
 
+
+window.notifications = new notificationBox(document.getElementById('notification-box') as HTMLDivElement, 5);
+
+
 const get = (id: string): HTMLElement => document.getElementById(id);
 const text = (id: string, val: string) => { document.getElementById(id).textContent = val; };
 const html = (id: string, val: string) => { document.getElementById(id).innerHTML = val; };
@@ -341,6 +345,18 @@ const serialize = () => {
         if (req.readyState == 4) {
             toggleLoader(restartButton);
             if (req.status == 500) {
+                if (req.response == null) {
+                    const old = restartButton.textContent;
+                    restartButton.classList.add("~critical");
+                    restartButton.classList.remove("~urge");
+                    restartButton.textContent = window.lang.strings("errorUnknown");
+                    setTimeout(() => {
+                        restartButton.classList.add("~urge");
+                        restartButton.classList.remove("~critical");
+                        restartButton.textContent = old;
+                    }, 5000);
+                    return;
+                }
                 if (req.response["error"] as string) {
                     const old = restartButton.textContent;
                     restartButton.classList.add("~critical");
@@ -363,7 +379,11 @@ const serialize = () => {
                 window.location.href = host;
             };
         }
-    }, true, () => {});
+    }, true, (req: XMLHttpRequest) => {
+        if (req.status == 0) {
+            window.notifications.customError("connectionError", window.lang.strings("errorConnectionRefused"));
+        }
+    });
 }
 restartButton.onclick = serialize;
 
@@ -562,7 +582,11 @@ window.onpopstate = (event: PopStateEvent) => {
                     button.classList.remove("~positive");
                 }, 5000);
             }
-        }, true, () => {});
+        }, true, (req: XMLHttpRequest) => {
+            if (req.status == 0) {
+                window.notifications.customError("connectionError", window.lang.strings("errorConnectionRefused"));
+            }
+        });
     };
 })();