yes you can get the screen width using window object

inside your onInit in TS

  import { HostListener } from '@angular/core';
  public innerWidth: any;
  ngOnInit() {
    this.innerWidth = window.innerWidth;
  }
  @HostListener('window:resize', ['$event'])
  onResize(event) {
  //you'll get the width
    this.innerWidth = window.innerWidth;
    console.log('this.innerWidth', this.innerWidth);
  }

Add your warning code inside onResize or handle accordingly.

We use hostlistener to check window size during resize, but we also check width on component init ngOnInit() because component might start without resize event.

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss'],
  host: {
    '(window:resize)': 'onWindowResize($event)',
  },
})
export class AppComponent implements OnInit {
  name = 'Angular';
  width: number = window.innerWidth;
  height: number = window.innerHeight;
  goodWidth: number = 1600;

  ngOnInit(): void {
    this.getInitSize();
  }

  getInitSize() {
    this.width = window.innerWidth;
    this.height = window.innerHeight;
    this.shouldAlert();
  }

  onWindowResize(event) {
    this.width = event.target.innerWidth;
    this.height = event.target.innerHeight;
    this.shouldAlert();
  }

  shouldAlert() {
    if (this.width < this.goodWidth) {
      window.alert(
        'warning message to the user if user is trying to view the application with less than 1600 width'
      );
    }
  }
}

Working example: https://stackblitz.com/edit/angular-window-width-1qbtpx?file=src%2Fapp%2Fapp.component.ts