added under construction warning to quick analysis

src/app/services/analysis/analysis.service.ts

@@ -4,9 +4,16 @@ import {HttpClient} from '@angular/common/http';
 import {environment} from '../../../environments/environment';
 import {toast} from 'bulma-toast';
 import {Injectable} from '@angular/core';
-import { NetexControllerService } from '../netex-controller/netex-controller.service';
-
-export type AlgorithmType = 'trustrank' | 'keypathwayminer' | 'multisteiner' | 'closeness' | 'degree' | 'proximity' | 'betweenness';
+import {NetexControllerService} from '../netex-controller/netex-controller.service';
+
+export type AlgorithmType =
+  'trustrank'
+  | 'keypathwayminer'
+  | 'multisteiner'
+  | 'closeness'
+  | 'degree'
+  | 'proximity'
+  | 'betweenness';
 export type QuickAlgorithmType = 'quick' | 'super';
 
 export const algorithmNames = {
@@ -252,6 +259,19 @@ export class AnalysisService {
       return;
     }
 
+    if (dataset == null) {
+      toast({
+        message: `Passed dataset is null. This feature might be still under development.`,
+        duration: 5000,
+        dismissible: true,
+        pauseOnHover: true,
+        type: 'is-danger',
+        position: 'top-center',
+        animate: {in: 'fadeIn', out: 'fadeOut'}
+      });
+      return;
+    }
+
     this.launchingQuick = true;
 
     const resp = await this.http.post<any>(`${environment.backend}task/`, {