classify.es6

function classify(mixin) {
  const Surrogate = class {};
  Surrogate.prototype = mixin;
  return Surrogate;
}

const baseProto = {
  sayHello() {
    console.log('hello');
  }
};

class Subclass extends classify(baseProto) {
  callBaseSayHello() {
    this.sayHello();
  }
}