Getting element height

The correct way is to use @ViewChild() decorator:

https://angular.io/docs/ts/latest/api/core/index/ViewChild-decorator.html

Template:

<div class="view-main-screen" #mainScreen></div>

Component:

import { ElementRef, ViewChild } from '@angular/core';

export class viewApp{

      @ViewChild('mainScreen') elementView: ElementRef;
      viewHeight: number;

      constructor() {
      }

      clickMe(){
        this.viewHeight = this.elementView.nativeElement.offsetHeight;
      }
}

That should do it but obviously you need to add your Component decorator.

Edit:

For Angular 8 or later you need to provide the 2nd parameter in ViewChild

@ViewChild('mainScreen', {read: ElementRef, static:false}) elementView: ElementRef;