CodeMirror

class Greeter {

  greeting: string;

  constructor (message: string) {

    this.greeting = message;

  }

  greet() {

    return "Hello, " + this.greeting;

  }

}   

​

var greeter = new Greeter("world");

​

var button = document.createElement('button')

button.innerText = "Say Hello"

button.onclick = function() {

  alert(greeter.greet())

}

​

document.body.appendChild(button)

​

​