test.es6

function _overload(all, target, name, descriptor) {
  if (!target.__$$methods) {
    target.__$$methods = {};
    target.__$$methods[name] = [];
    target.__$$methods[name].push({len: descriptor.value.length, fn: descriptor.value, all: all});
  } else {
    target.__$$methods[name].push({len: descriptor.value.length, fn: descriptor.value, all: all});
  }

  descriptor.value = function () {
    let length = arguments.length;
    let fn = this.__$$methods[name].filter((item)=>(item.len == length || item.all)).pop();
    if (!fn) {
      throw new Error('no fn defined');
    }
    this::fn.fn(...arguments);
  }
}
function overload(all) {
  if (arguments.length == 3) {
    return _overload(false, ...arguments);
  }
  return _overload.bind(null, all);
}

////////////////// overload 测试
class Base {
  constructor() {

  }

  @overload(true)
  fn() {
    console.log('print all', arguments);
  }

  @overload
  fn(a, b, c) {
    console.log('from 3', a, b, c);
  }

  fn2() {
    console.log('fn2, print from base');
  }
}


class ClassA extends Base {
  @overload
  fn(a) {
    console.log(a);
  }

  fn2() {
    console.log(super.fn2);
    super.fn2();
    console.log('fn2 from Class A');

  }
}
var test = new ClassA();
test.fn(1);
test.fn();
test.fn(1, 2, 3);
test.fn(1, 2, 3, 4);
test.fn2();

//////////////////////// overload class的测试

function overloadClass(target) {
  console.log(target.name);
  console.log(target.length);
  console.dir(Object.getOwnPropertyNames(target.prototype));
  console.dir(target.prototype);
}

@overloadClass
class Base2 {
  constructor() {

  }

  fn() {
  }
}


@overloadClass
class ClassB extends Base2 {
  constructor(b) {
    super();
  }

  fn() {
  }

  fn2() {
  }

  fn(b) {
    console.log('test');
  }

  fn(a, b, c) {
    console.log('test3');
  }
}