根据配置文件加载js依赖模块

要求：

根据下面的配置文件

module=[

{'name':'jquery','src':'/js/lib/jquery-1.8.3.js'},

{'name':'swfobject','src':'/js/utils/swfobject.js'},

{'name':'fancybox','src':'/js/jquery/jquery.fancybox.js','require':['jquery']},

{'name':'uploadify','src':'/js/utils/uploadify.js','require':['swfobject']},

{'name':'jqform','src':'/js/jquery/jquery.form.js','require':['jquery']},

{'name':'register','src':'/js/page/reg.js','require':['jqform']},

{'name':'login','src':'/js/page/login.js','require':['fancybox','jqform']},

{'name':'upload','src':'/js/page/upload.js','require':['fancybox','jqform','uploadify']}

]

写一个函数

def getfiles(name)

返回 加载某个name指定的页面，要加载的js文件列表，有依赖的要先加载

小菜解法

    此题粗看起来很简单，实则不然。

     难点在于依赖模块的加载时机。假如有这样的依赖关系：A-B&C、B-C，A模块依赖B模块和C模块，同时B模块又依赖了C模块，总不能让C加载两次吧！

     小菜给出的这个解法，只是一个思路，肯定有比这更好的算法，小菜觉得可以用二叉树之类的算法解决，但小菜不会呀~~~

     此算法没有考虑循环依赖的情景。

     代码如下：

 /**

  * 不考虑循环依赖

  * @type {Function}

  */

 var loadModule = (function(){

     /**

      * 业务逻辑封装

      * @type {{chainHead: {}, chainCurrent: {}, srcCache: {}, main: main, load: load, findModule: findModule}}

      */

     var logics = {

         chainHead: {},     //链表头

         chainCurrent: {},  //链表当前节点

         srcCache: {},      //module src 缓存

         /**

          * 对外接口

          * @param modules  配置对象

          * @param name  模块名称

          * @returns {Array} 依赖模块列表，按照加载先后顺序排列

          */

         main: function(modules, name){

             var nameArray = [],  //模块名称列表

                 srcArray = [],   //依赖模块列表

                 nameStr = "",    //模块名称字符串集

                 repeatRegex = /(^| )([\w]+ ).*\2/,  //模块名称去重正则

                 i = 0;

             //粗略加载所有依赖模块

             this.load(modules, name)

             //构造模块名称字符串集

             this.chainCurrent = this.chainHead;

             while(this.chainCurrent.next){

                 nameArray.push(this.chainCurrent.name);

                 this.chainCurrent = this.chainCurrent.next;

             }

             nameStr = nameArray.join(" ") + " ";  //统一标准，末尾补一个空格

             //依赖模块去重

             while(repeatRegex.exec(nameStr)){

                 nameStr = nameStr.replace(repeatRegex, function(g0, g1, g2){

                     return g0.substring(0, (g0.length - g2.length));

                 });

             }

             nameStr = nameStr.substring(0, (nameStr.length - 1));  //去掉补充的多余空格

             //依赖模块名称转换为模块路径

             nameArray = nameStr.split(" ");

             for(i = 0; i < nameArray.length; i++){

                 srcArray.push(this.srcCache[nameArray[i]]);

             }

             return srcArray;

         },

         /**

          * 递归加载模块

          * @param modules  配置对象

          * @param name  模块名称

          */

         load: function(modules, name){

             var node = {},

                 module = this.findModule.call(modules, "name", name),

                 i = 0;

             //判断模块是否存在

             if(!module){

                 throw Error("依赖模块 " + name +" 未找到");

             }

             //构造模块依赖链表

             node.name = name;

 //            node.src = module.src;

             this.srcCache[name] = module.src;

             node.next = this.chainHead;

             this.chainHead = node;

             //递归依赖

             if(module.require && module.require.length){

                 for(i = 0;i < module.require.length; i++){

                     this.load(modules, module.require[i]);

                 }

             }

         },

         /**

          * 根据指定属性名称和属性值查找模块

          * @param name  属性名称

          * @param value  属性值

          * @returns {*}

          */

         findModule: function(name, value){

             var array = this,

                 item = {},

                 i = 0;

             //遍历模块

             for(i = 0; i < array.length; i++){

                 item = array[i];

                 //获取指定模块

                 if(item && item[name] === value){

                     return item;

                 }

             }

             //找不到返回null

             return null;

         }

     };

     //暴露对外接口

     return function(){

         return logics.main.apply(logics, arguments);

     };

 }());

 /**

  * Test Usecase

  * @type {*[]}

  */

 var modules=[

     {'name':'jquery','src':'/js/lib/jquery-1.8.3.js'},

     {'name':'swfobject','src':'/js/utils/swfobject.js'},

     {'name':'fancybox','src':'/js/jquery/jquery.fancybox.js','require':['jquery']},

     {'name':'uploadify','src':'/js/utils/uploadify.js','require':['swfobject']},

     {'name':'jqform','src':'/js/jquery/jquery.form.js','require':['jquery']},

     {'name':'register','src':'/js/page/reg.js','require':['jqform']},

     {'name':'login','src':'/js/page/login.js','require':['fancybox','jqform']},

     {'name':'upload','src':'/js/page/upload.js','require':['fancybox','jqform','login','uploadify']}

 ];

 console.log(loadModule(modules, "upload"));