import {Directive, Input, EventEmitter, ElementRef, Renderer, Inject, AfterViewInit, OnChanges } from '@angular/core';
 
@Directive({
  selector: '[focus]'
})
export class FocusDirective implements OnChanges {
  @Input('focus') focus: boolean;
 
  constructor(@Inject(ElementRef) private element: ElementRef, private renderer: Renderer) {
  }
 
  ngOnChanges() {
    if (this.focus) {
      this.renderer
        .invokeElementMethod(this.element.nativeElement, 'focus', []);
    }
  }
 
 
}