JSFiddle - React, Tailwind, and code Playground

HTML

<button onclick="testList.push(new Test());">run</button>

JavaScript

testList = [];

Test = function(){
	   this.y = 25;
       that = this;
	   this.interval = setInterval(function(){
			that.y += that.dy;
			if (that.y>300){
			    console.log(that.y);
				clearInterval(that.interval);
			}
	   }, 10);
	}