Angular variable is not updating when I return to previous page

Ionic Framework Ionic Angular
5

Thanks for the link provided, I think I understood the differences and how you solved the problem, I found it strange that in the tutorial they don’t approach it that way. I even wonder if this problem is intentional, by some incomplete way of the tutorial, or if was my fault beacause some mistake I made. I ended up using the lifecycle hook as a last measure, I know that Angular alone manages change detection, but even that didn’t work. I tried to make some changes using your method but it also didn’t work:

hero.service.ts

public heroes = new BehaviorSubject<Hero[] | null>(null);

getHeroes(): Observable<Hero[]>{
 	return this.http.get<Hero[]>(this.heroesUrl)
    .pipe(
        tap(res=>{ 
         this.log('fetched heroes');
         this.heroes.next(res); 
        }),
       catchError(this.handleError<Hero[]>('getHeroes', []))
    );
}

watchHeroes(): Observable<Hero[]> { return this.heroes; }
 updateHero(hero:Hero):Observable<any>{
   return this.http.put(this.heroesUrl, hero, this.httpOptions).pipe(
     tap(res =>{
       this.log(`updated hero id=${hero.id}`)
       this.getHeroes();
     }),
     catchError(this.handleError<any>('updateHero'))
    );
}

hero-detail.component.ts

hero:Hero;
  
constructor(
	private route: ActivatedRoute,
	private heroService: HeroService,
	private location: Location
	) { }

ngOnInit() {
	this.getHero();
}

getHero(): void{
	const id = +this.route.snapshot.paramMap.get('id');
	this.heroService.getHero(id).subscribe(hero => this.hero = hero);
}

goBack(): void{
	this.location.back();
}

save(): void{
  this.heroService.updateHero(this.hero)
  .subscribe(() => this.goBack());
}

dashboard.component.ts

heroes$:Observable<Hero[]> = new Observable<Hero[]>();
heroes:Hero[] = [];

ngOnInit() {
  	this.getHeroes();
    this.heroes$.subscribe(res => {
        return this.heroes = res;
    });
} 
 
getHeroes():void{
	this.heroService.getHeroes().subscribe(_ =>this.heroes$ = this.heroService.watchHeroes());
}

Note: @Tommertom, I don’t know if I understand your question, but I’m using ionic 5 and I adapted the tutorial solution for the app.