接口：利 固化一部分代码 弊 丧失js的灵活性

在JavaScript中模仿接口

/*interface Composite{    function add(child);    function remove(child);    function getChild(index);}interface FormItem{    function save();}*/var CompositeForm=function(id,method,action){    ...};CompositeForm.prototype.add = function(child) {    ...};CompositeForm.prototype.remove = function(child) {    ...};CompositeForm.prototype.getChild = function(index) {    ...};CompositeForm.prototype.save = function() {    ...};

改进一下，用属性检查

/*interface Composite{    function add(child);    function remove(child);    function getChild(index);}interface FormItem{    function save();}*/var CompositeForm=function(id,method,action){    this.implementsInterfaces=['Composite','FormItem'];    ...};...function addForm(formInstance){    if (!implements(formInstance,'Composite','FormItem')) {        throw new Error("Object does not implement a required interface.");    }    ...}function implements(Object){    for(var i=1;i

用鸭式辨型模仿接口

var Composite =new Interface('Composite',['add','remove','getChild']);var FormItem=new Interface('FormItem',['save']);var CompositeForm=function(id,method,action){    ...};...function addForm(formInstance){    ensureImplements(formInstance,Composite,FormItem);    ...}

结合第一种和第三种

 

var Composite =new Interface('Composite',['add','remove','getChild']);var FormItem=new Interface('FormItem',['save']);var CompositeForm=function(id,method,action){    ...};...function addForm(formInstance){    Interface.ensureImplements(formInstance,Composite,FormItem);    ...}

Interface类的定义

var Interface=function(name,method){    if(arguments.length!=2){        throw new Error("需要2个参数");    }    this.name=name;    this.method=[];    for(var i=0,len=methods.length;i