JavaScript design mode 2

Interface: The benefits of curing part of the code cheat loss JS Flexibility

imitating interfaces in JavaScript

/* interface composite{    function Add (child);    function remove (child);    function Getchild (index);} Interface formitem{    function Save ();} */ var compositeform=function(id,method,action) {    function(child) {     function (Child) {    function(index) {    function() {    ...};

Improve, check with attributes

/*interface composite{function Add (child);    function remove (child); function Getchild (index);} Interface formitem{function Save ();}*/varcompositeform=function(id,method,action) { This. implementsinterfaces=[' Composite ', ' FormItem ']; ...}; ...functionAddForm (forminstance) {if(!implements (forminstance, ' Composite ', ' FormItem ')) {        Throw NewError ("Object does not implement a required interface."); }    ...}functionimplements (Object) { for(vari=1;i<arguments.length;i++){        varInterfacename=Arguments[i]; varInterfacefound=false;  for(varj=0;j<object.implementsinterfaces.length;j++){            if(object.implementsinterfaces[j]==InterfaceName) {Interfacefound=true;  Break;        }; }        if(!interfacefound) {            return false;    }; }    return true;}

Using duck type to imitate interface

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);    ...}

Combined with the first and third types of

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);    ...}

Definition of the interface class

varInterface=function(name,method) {if(arguments.length!=2){        Throw NewError ("2 parameters required"); }     This. name=name;  This. method=[];  for(vari=0,len=methods.length;i<len;i++){        if(typeofmethods[i]== ' String '){            Throw NewError ("Need to be a string"); }         This. Methods.push (Methods[i]); }};interface.ensureimplements=function(object) {if(arguments.length<2){        Throw NewError ("Minimum of 2 parameters required"); }     for(vari=1,len=arguments.length;i<len;i++){        varInterface=Arguments[i]; if(interface.constructor!=Interface) {            Throw NewError ("Requires 2 parameters and is an instance of interface"); }         for(varj=0,methodslen=interface.methods.length;j<methodslen;j++){            varMethod=Interface.methods[j]; if(!object[method]| |typeofobject[method]!== ' function ') {                Throw NewError (' Method not found ');        }; }    }};

JavaScript design mode 2