Makes numbers animate from a number to another number (using IntersectionObserver API)

animated-counter-intersectionObserver.js

jQuery(document).ready(function(){
	//jQuery('#rs-fullwidth-helper1').before('<p style="color:black;">testing4</p>');
	function countUp() {

		jQuery('.counter').each(function() {
			  var counter = jQuery(this),
			      countTo = counter.attr("data-count");
			  
			  jQuery({ countNum: counter.text()}).animate({
			    countNum: countTo
			  },

			  {

			    duration: 3000,
			    easing:"swing",
			    step: function() {
			      counter.text(Math.floor(this.countNum));
			    },
			    complete: function() {
			      counter.text(this.countNum);
			      //alert("finished");
			    }

			  });  
			  
			});

	}
//  Make sure to include the polyfill script for non-compatible browsers (IntersectionObserver)
//  https://www.npmjs.com/package/intersection-observer#browser-support
	const images = document.querySelectorAll('.counter');

	observer = new IntersectionObserver((entries) => {
	  entries.forEach(entry => {
	    if (entry.intersectionRatio > 0) {

	    	countUp();
	      
	    } else {
	      var allCounters = document.querySelectorAll(".counter");
	      [].forEach.call(allCounters, function(allCounters) {
	        allCounters.innerHTML = "0";
	      });
	    }
	  });
	});

	images.forEach(image => {
	  observer.observe(image);
	}); 

});