function overLoading() {// 根据 arguments.length 判断switch (arguments.length) {case 0:/* 传入0个参数时执行的代码 */break;case 1:/* 传入1个参数时执行的代码 */break;case 2:/* 传入2个参数时执行的代码 */break;/* 还有好多······ */}
}

var people = {values: ["Dean Edwards", "Sam Stephenson", "Alex Russell", "Dean Tom"]
};

addMethod(people, "find", function() {}); /*不传参*/
addMethod(people, "find", function(a) {}); /*传一个*/
addMethod(people, "find", function(a, b) {}); /*传两个*/

function addMethod(object, name, fn) {var old = object[name]; // 使用临时变量接收 object 的 name 方法object[name] = function () { // 定义name方法/*this 指向 objectfn.length 指 fn参数的长度arguments.length 指得是name()方法中的参数// 当调用不同参数的fn时，会每次匹配所有的fn，发生递归*/if(fn.length === arguments.length) {return fn.apply(this, arguments);} else if (typeof old === "function") {return old.apply(this, arguments);}}

 //addMethodfunction addMethod(object, name, fn) {var old = object[name];object[name] = function () {console.log(fn.length);console.log(arguments.length);console.log(typeof old);if (fn.length === arguments.length) {return fn.apply(this, arguments);} else if (typeof old === "function") {return old.apply(this, arguments);}}}var people = {values: ["Dean Edwards", "Alex Russell", "Dean Tom"]};/* 下面开始通过addMethod来实现对people.find方法的重载 */// 不传参数时，返回peopld.values里面的所有元素addMethod(people, "find", function () {return this.values;});// 传一个参数时，按first-name的匹配进行返回addMethod(people, "find", function (firstName) {var ret = [];for (var i = 0; i < this.values.length; i++) {if (this.values[i].indexOf(firstName) === 0) {ret.push(this.values[i]);}}return ret;});// 传两个参数时，返回first-name和last-name都匹配的元素addMethod(people, "find", function (firstName, lastName) {var ret = [];for (var i = 0; i < this.values.length; i++) {console.log(firstName + " " + lastName);if (this.values[i] === (firstName + " " + lastName)) {ret.push(this.values[i]);}}return ret;});// 测试：console.log(people.find()); //["Dean Edwards", "Alex Russell", "Dean Tom"]console.log(people.find("Dean")); //["Dean Edwards", "Dean Tom"]console.log(people.find("Dean","Edwards")); //["Dean Edwards"]