ADD: more error handlers

frontend/src/main.js

@@ -300,12 +300,15 @@ async function init() {
     window.console.log(err, info)
     EventBus.$emit('error', err)
   }
-
   window.onerror = function (message, source, lineno, colno, error) {
     window.console.debug('window-error handler triggered')
     window.console.log(error)
     EventBus.$emit('error', error)
   }
+  window.addEventListener('unhandledrejection', function (event) {
+    window.console.debug('unhanldedrejection handler triggered')
+    EventBus.$emit('error', event.reason)
+  })
   Axios.interceptors.response.use(
     function (response) {
       return response