compiled.js

// ...

function loggableClass(target) {
    console.log("Class: %s", target.name);

    return target;
}

function loggableMethod(target, name, descriptor) {
    console.log("Method: %s", name);

    return descriptor;
}

var Klass = (function () {
    function Klass() {
        _classCallCheck(this, _Klass);
    }

    var _Klass = Klass;

    _createDecoratedClass(_Klass, [{
        key: "hello",
        decorators: [loggableMethod],
        value: function hello() {
            console.log("world");
        }
    }]);

    Klass = loggableClass(Klass) || Klass;
    return Klass;
})();