Resolve "Consistent error handling in frontend"

Closes #148 (closed)

frontend/src/util/helpers.ts

@@ -150,7 +150,7 @@ export function parseErrorNotification (response: AxiosResponse): string {
   if (!response.data || Object.keys(response.data).length === 0) {
     return 'There is no useful error data. Please ask the staff for help.'
   } else {
-    let msg = "";
+    let msg = "<ul>";
     function pickRecursive(obj: any) {
       if (obj instanceof Object) {
           for (let k of Object.keys(obj)) {
@@ -161,6 +161,7 @@ export function parseErrorNotification (response: AxiosResponse): string {
       }
     }
     pickRecursive(response.data)
+    msg += "</ul>"
 
     if (response.status === 404) {
       msg += "<br/>If you experience unusual behaviour, finish all unfinished work and relog." +