applynew.js

class MyClass {
  constructor(a, b, c) {
    this.sum_ = a + b + c;
  }
  sum() {
    return this.sum_;
  }
}

console.log(new MyClass(2, 3, 4).sum());

var applyNew = function(ctor, args) {
  var bind = Function.prototype.bind;
  var c = bind.apply(ctor, [null].concat(args));
  return new c();
};

console.log(applyNew(MyClass, [2, 3, 4]).sum());