Function overloading for Javascript

overloading.js

/**
 *
 * @authors     yuChuanXi (http://yuchuanxi.com, wangfei.f2e@gmail.com)
 * @date        2016-03-23 10:12:03
 * @title       title
 * @description description
 */
'use strict';

// js 模拟重载函数 1
function addMethod ( obj, name, fn ) {
  var old = obj[name];

  obj[name] = function () {
    if ( fn.length === arguments.length ) {
      return fn.apply(this, arguments);
    }
    else {
      return old.apply(this, arguments);
    }
  }
}

// js 模拟重载函数 2
var addMethod2 = (function () {
  var
    cache = {};

  return function ( obj, name, fn ) {

    obj[name] || (obj[name] =  function () {
      cache[arguments.length].apply(this, arguments);
    });

    cache[fn.length] = fn;
  }
}());

// js 模拟重载函数 3
function addMethod3 ( obj, name, fn ) {

  obj[name] || (obj[name] = function () {
    addMethod3[arguments.length].apply(this,arguments);
  });

  addMethod3[fn.length] = fn;
}

// eg:
var
  ninja1 = {},
  ninja2 = {},
  ninja3 = {};

addMethod(ninja1, 'whatever', function () {
  console.log(111)
});
addMethod(ninja1, 'whatever', function (a) {
  console.log(a)
});
addMethod(ninja1, 'whatever', function (a, b) {
  console.log(a, b)
});
ninja1.whatever();
ninja1.whatever('a');
ninja1.whatever('a', 'b');

addMethod2(ninja2, 'whatever', function () {
  console.log(111)
});
addMethod2(ninja2, 'whatever', function (a) {
  console.log(a)
});
addMethod2(ninja2, 'whatever', function (a, b) {
  console.log(a, b)
});
ninja2.whatever();
ninja2.whatever('a');
ninja2.whatever('a', 'b');

addMethod3(ninja3, 'whatever', function () {
  console.log(111)
});
addMethod3(ninja3, 'whatever', function (a) {
  console.log(a)
});
addMethod3(ninja3, 'whatever', function (a, b) {
  console.log(a, b)
});
ninja3.whatever();
ninja3.whatever('a');
ninja3.whatever('a', 'b');

// 这样真的好吗
addMethod3(window, 'whatever', function () {
  console.log(111)
});
addMethod3(window, 'whatever', function (a) {
  console.log(a)
});
addMethod3(window, 'whatever', function (a, b) {
  console.log(a, b)
});
whatever();
whatever('a');
whatever('a', 'b');