save dialog

src/app/modules/songs/song/edit/edit-song.guard.ts

@@ -0,0 +1,19 @@
+import {Injectable} from '@angular/core';
+import {ActivatedRouteSnapshot, CanDeactivate, RouterStateSnapshot, UrlTree} from '@angular/router';
+import {Observable} from 'rxjs';
+import {EditComponent} from './edit.component';
+
+@Injectable({
+  providedIn: 'root'
+})
+export class EditSongGuard implements CanDeactivate<unknown> {
+  canDeactivate(
+    component: EditComponent,
+    currentRoute: ActivatedRouteSnapshot,
+    currentState: RouterStateSnapshot,
+    nextState?: RouterStateSnapshot): Observable<boolean | UrlTree> | Promise<boolean | UrlTree> | boolean | UrlTree {
+
+    return component.editSongComponent.askForSave(nextState);
+  }
+
+}