JSFiddle - React, Tailwind, and code Playground

CoffeeScript

class Widget
  @count: 0
  @addWidget: -> @count++
  constructor: ->
    Widget.addWidget()

w = new Widget
w2 = new Widget
w3 = new Widget

$('body').append 'Widget.count: ' + Widget.count
$('body').append '<br>'
$('body').append '@constructor.count: ' + w.constructor.count