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

@Directive({
    selector: '[appMyFirstDirective]'
})
export class MyFirstDirectiveDirective {

    constructor(private element: ElementRef){}

    @HostListener('mouseenter')
    public onMouseEnter(){
        this.element.nativeElement.style.backgroundColor = "red";
    }

    @HostListener('mouseleave')
    public onMouseLeave(){
        this.element.nativeElement.style.backgroundColor = "green";
    }

}