JSFiddle - React, Tailwind, and code Playground

HTML

<html>
  <head></head>
  <body>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/phaser/2.4.8/phaser.js"></script>
  </body>
</html>

JavaScript

(function(){
 var game = new Phaser.Game(400, 400, Phaser.WEBGL, null, {
   create: function(){
     var graphic  = this.game.add.graphics(0, 0);
     var rect     = new Phaser.RoundedRectangle(0, 0, 100, 100, 10);
     
     graphic.beginFill(0xff0000);
     graphic.drawShape(rect);
     graphic.endFill();
     
     this.add.tween(rect).to({width: 400, radius: 0}, 4000, Phaser.Easing.Linear.None, true);
   }
 });
}())