Answers for "how to refresh a part of component in angular"

refresh current component angular

reloadCurrentRoute() {
    let currentUrl = this._router.url;
    this._router.navigateByUrl('/', {skipLocationChange: true}).then(() => {
        this._router.navigate([currentUrl]);
        console.log(currentUrl);
    });
  }

How to Reload a Component in Angular

reloadComponent() {
  let currentUrl = this.router.url;
      this.router.routeReuseStrategy.shouldReuseRoute = () => false;
      this.router.onSameUrlNavigation = 'reload';
      this.router.navigate([currentUrl]);
  }

reload sub component angular

this.router.navigateByUrl('/RefreshComponent', { skipLocationChange: true }).then(() => {
    this.router.navigate(['Your actualComponent']);
});