1     function traverse(objNmae,obj,url){
 2         url = url || objNmae;
 3         if(typeof obj === "object" ){
 4             //for in 方法
 5             for(let i in obj){
 6                 url += ("=>"+i);
 7                 arguments.callee(i,obj[i],url);
 8             }
 9             //
 
forEach 方法
10             obj.forEach(function(value,index){
11                 url += ("=>"+index);
12                 arguments.callee(index,value,url);
13             });
14         }else if(typeof obj === "string" || typeof obj === "number"){
15             console.log(url+objNmae+":"+obj);
 
16             return;
17         }
18     }

for in 方法 和forEach方法，方法的功能是同樣的，就是遍歷一個對象集，並且輸出對象中所有末端元素的路徑。

接下來我們對下面的這個對象進行遍歷

     var itg_data        = [{"itg_num":"1200","itg_category":"rew_gold","itg_reward_num":"1","itg_sum_num":"661","itg_place":"","pic":"\/Uploads\/game\/reward\/357203060783037259.png","goods_unit":"\u679a","goods_name":null
 
},{"itg_num":"1400","itg_category":"rew_goods","itg_reward_num":"4","itg_sum_num":"656","itg_place":"fresh","pic":"\/Uploads\/UploadsShop\/2017-07-05\/595c823c86cf7.jpg","goods_unit":"\u679a","goods_name":"\u65e0\u6297\u571f\u9e21\u86cb"},{"itg_num":"1600","itg_category":"rew_gold","itg_reward_num":"2","itg_sum_num":"555","itg_place":"","pic":"\/Uploads\/game\/reward\/357203060783037259.png","goods_unit":"\u679a","goods_name":null},{"itg_num":"1800","itg_category":"rew_goods","itg_reward_num":"8","itg_sum_num":"492","itg_place":"fresh","pic":"\/Uploads\/UploadsShop\/2017-07-05\/595c823c86cf7.jpg","goods_unit":"\u679a","goods_name":"\u65e0\u6297\u571f\u9e21\u86cb"},{"itg_num":"2500","itg_category":"rew_goods","itg_reward_num":"1","itg_sum_num":"555","itg_place":"fresh","pic":"\/Uploads\/UploadsShop\/2017-06-22\/594b602919d9d.jpg","goods_unit":"\u53ea","goods_name":"\u6bcd\u9e21\uff08\u6563\u517b\uff09"}];

for in 方法

但是在這裏 forEach方法會報錯，

提示最大調用棧大小超過。但是使用for in 就沒有這樣的問題

由此可見，forEach在遞歸中因為，有些對象樹過深，對導致其堆棧溢出，forEach不適合用在遞歸中，可以使用for in

遞歸中，調用forEach方法問題