async ngOnInit

interface OnInit {
    ngOnInit(): void;
}

class stackoverflow implements OnInit {
    async ngOnInit() {
        return await new Promise(res => {
            setTimeout(() => {
                alert('ngOnInit');
                res();
            }, 2000);
        })
    }

    afterngOnInit() {
        alert('should i be called after ngOnInit???');
    }
}

let s = new stackoverflow();
s.ngOnInit();
s.afterngOnInit();