What are directives - amresh087/newronaRepos GitHub Wiki

Directives add behaviour to an existing DOM element or an existing component instance.

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

   @Directive({ selector: '[myHighlight]' })
   export class HighlightDirective {
       constructor(el: ElementRef) {
          el.nativeElement.style.backgroundColor = 'yellow';
       }
   }

Now this directive extends HTML element behavior with a yellow background as below

  <p myHighlight>Highlight me!</p>