JSFiddle - React, Tailwind, and code Playground

JavaScript

var Foo = function(x, y){
   this.x = x;
   this.y = y;
   this.move = function(){
      x += 1;
      y += 1;
      alert(x + ' ' + ' ' + y);
   };
   Foo.instances.push(this);
};
Foo.instances = [];
Foo.moveAll = function(){
    for(var i = 0; i < Foo.instances.length; i++)
        Foo.instances[i].move();
}
    
var a = new Foo(5, 6);
var b = new Foo(3, 4);

Foo.moveAll();