Getting Started with Gulp - Add some TypeScript - https://github.com/SSWConsulting/training-content

greeter.ts

      class Greeter {
            constructor(public greeting: string) { }
            greet() {
               return "<h1>" + this.greeting + "</h1>";
          }
      };
      
      var greeter = new Greeter("Hello, world!");
          
      document.body.innerHTML = greeter.greet();