angular-tooltip-html/src/app/hasContent/hasContent.component.ts

import { Component, OnInit, ViewChild, ElementRef, AfterViewInit, Output, EventEmitter, Input } from '@angular/core';
import { Content } from '@angular/compiler/src/render3/r3_ast';

@Component({
  selector: 'app-content',
  templateUrl: './hasContent.component.html',
  styleUrls: ['./hasContent.component.css']
})
export class HasContentComponent implements AfterViewInit {
	@ViewChild('content') content: ElementRef;
	@Input() hasChild: Boolean = false;
	@Output() hasChildChange : EventEmitter<Boolean> = new EventEmitter<Boolean>()

  constructor() { }

	ngAfterViewInit(){
		this.hasChildChange.emit(!!this.content.nativeElement.childNodes.length);
	}

}