Fix error when deleting last element in list

js/src/trackviewmodel.js

@@ -277,11 +277,14 @@ export default class TrackViewModel extends ViewModel {
   }
 
   onTrackDeleted() {
-    const index = this.model.trackList.indexOf(this.state.currentTrack);
+    let index = this.model.trackList.indexOf(this.state.currentTrack);
     this.state.currentTrack = null;
     if (index !== -1) {
       this.model.trackList.splice(index, 1);
       if (this.model.trackList.length) {
+        if (index >= this.model.trackList.length) {
+          index = this.model.trackList.length - 1;
+        }
         this.model.currentTrackId = this.model.trackList[index].listValue;
       } else {
         this.model.currentTrackId = '';

js/src/userviewmodel.js

@@ -119,11 +119,14 @@ export default class UserViewModel extends ViewModel {
   }
 
   onUserDeleted() {
-    const index = this.model.userList.indexOf(this.state.currentUser);
+    let index = this.model.userList.indexOf(this.state.currentUser);
     this.state.currentUser = null;
     if (index !== -1) {
       this.model.userList.splice(index, 1);
       if (this.model.userList.length) {
+        if (index >= this.model.userList.length) {
+          index = this.model.userList.length - 1;
+        }
         this.model.currentUserId = this.model.userList[index].listValue;
       } else {
         this.model.currentUserId = '0';

js/test/trackviewmodel.test.js

@@ -632,6 +632,19 @@ describe('TrackViewModel tests', () => {
     expect(vm.state.currentTrack).toBe(null);
   });
 
+  it('should remove current last track from track list and set new current track id', () => {
+    // given
+    vm.model.trackList = [ track1, track2 ];
+    vm.state.currentTrack = track2;
+    vm.model.currentTrackId = track2.listValue;
+    // when
+    vm.onTrackDeleted();
+    // then
+    expect(vm.model.trackList.length).toBe(1);
+    expect(vm.model.currentTrackId).toBe(track1.listValue);
+    expect(vm.state.currentTrack).toBe(null);
+  });
+
   it('should remove last remaining element from track list and set empty track id', () => {
     // given
     vm.model.trackList = [ track1 ];

js/test/userviewmodel.test.js

@@ -281,6 +281,19 @@ describe('UserViewModel tests', () => {
     expect(vm.state.currentUser).toBe(null);
   });
 
+  it('should remove current last user from user list and set new current user id', () => {
+    // given
+    vm.model.userList = [ user1, user2 ];
+    vm.state.currentUser = user2;
+    vm.model.currentUserId = user2.listValue;
+    // when
+    vm.onUserDeleted();
+    // then
+    expect(vm.model.userList.length).toBe(1);
+    expect(vm.model.currentUserId).toBe(user1.listValue);
+    expect(vm.state.currentUser).toBe(null);
+  });
+
   it('should remove last remaining element from user list and set empty user id', () => {
     // given
     vm.model.userList = [ user1 ];