Fix notification operator (#673)

* refactor: success will be shown when source emits atleast one value

* refactor: fixing lint

Author: anandtiwary

projects/components/src/notification/notification.service.test.ts

@@ -1,6 +1,6 @@
 import { MatSnackBar } from '@angular/material/snack-bar';
 import { createServiceFactory, mockProvider, SpectatorService } from '@ngneat/spectator/jest';
-import { of, throwError } from 'rxjs';
+import { EMPTY, of, throwError } from 'rxjs';
 import { NotificationComponent, NotificationMode } from './notification.component';
 import { NotificationService } from './notification.service';
 
@@ -87,10 +87,11 @@ describe('NotificationService', () => {
 
   test('withNotification operator should work correctly', () => {
     spectator = createService();
+    const matSnackBar = spectator.inject(MatSnackBar);
 
     of(true).pipe(spectator.service.withNotification('success', 'failure')).subscribe();
 
-    expect(spectator.inject(MatSnackBar).openFromComponent).toHaveBeenLastCalledWith(
+    expect(matSnackBar.openFromComponent).toHaveBeenLastCalledWith(
       NotificationComponent,
       expect.objectContaining({
         horizontalPosition: 'left',
@@ -102,7 +103,7 @@ describe('NotificationService', () => {
 
     throwError('error').pipe(spectator.service.withNotification('success', 'failure')).subscribe();
 
-    expect(spectator.inject(MatSnackBar).openFromComponent).toHaveBeenLastCalledWith(
+    expect(matSnackBar.openFromComponent).toHaveBeenLastCalledWith(
       NotificationComponent,
       expect.objectContaining({
         horizontalPosition: 'left',
@@ -111,5 +112,10 @@ describe('NotificationService', () => {
         data: expect.objectContaining({ message: 'failure', mode: NotificationMode.Failure })
       })
     );
+
+    // Completing the source observable without emitting a value should not show any message
+    matSnackBar.openFromComponent.mockClear();
+    EMPTY.pipe(spectator.service.withNotification('success', 'failure')).subscribe();
+    expect(matSnackBar.openFromComponent).not.toHaveBeenCalled();
   });
 });

projects/components/src/notification/notification.service.ts

@@ -1,6 +1,6 @@
 import { Injectable } from '@angular/core';
 import { MatSnackBar, MatSnackBarConfig, MatSnackBarRef } from '@angular/material/snack-bar';
-import { EMPTY, noop, Observable, Subject } from 'rxjs';
+import { EMPTY, Observable, Subject } from 'rxjs';
 import { tap } from 'rxjs/operators';
 import { NotificationComponent, NotificationMode } from './notification.component';
 import { NotificationModule } from './notification.module';
@@ -51,11 +51,13 @@ export class NotificationService {
   }
 
   public wrapWithNotification<T>(source: Observable<T>, successMessage: string, failureMessage: string): Observable<T> {
+    let emitted = false;
+
     return source.pipe(
       tap(
-        noop,
+        () => (emitted = true),
         () => this.createFailureToast(failureMessage),
-        () => this.createSuccessToast(successMessage)
+        () => emitted && this.createSuccessToast(successMessage)
       )
     );
   }