• Reduce using if statements in observer by using filter pipe

/* Avoid using */
confirmationDialog.afterClosed().subscribe(confirmed => {
  if (confirmed) {
    // do something
  }
});

/* Suggestion */
confirmationDialog.afterClosed()
.pipe(filter(confirmed => !!confirmed))
.subscribe(confirmed => {
  // do something
});

• Injected services should have readonly attribute

constructor(
  private readonly _notification: NotificationService,
) {
}

• Should add public access modifiers to property of a class (model)

export class Entity {
  public id: number;
  public name: string;
}