javascript JS递归遍历对象 使用for(variable in object)或者叫for/in和forEach方式

1.递归遍历查找特定key值(ie9以下不支持forEach)

原文http://www.cnblogs.com/ae6623/p/5938560.html

var obj = {
     first: "1",
     second: {
         name: "abc",
         mykey: "2",
         third: {
             age: "30",
             mykey: "3"
         }
     },
     forth: "4",
     mykey: "5"
 };
 
 console.log(getMykey(obj, []));
 
 function getMykey(obj, mykeyValues) {
     //没有则跳出
     if (!obj["mykey"]) {
         return mykeyValues;
     } else {
         //有就放入
         mykeyValues.push(obj["mykey"]);
         //再次递归
         var keys = Object.keys(obj);
         keys.forEach(function(i) {
             getMykey(obj[i], mykeyValues);
         });
     }
     return mykeyValues;
 }

2.递归遍历输出key

参考http://www.jb51.net/article/86607.htm

要求输出嵌套json对象的key name

LG: var tree = {node1:{node2:"",node3:{node4:""}}}
 
Print: ["node1","node2","node3","node4"]

答案：

var arr=[];
function printTree(tree){
for(var i in tree){
arr.push(i);
typeof tree[i]=='object'?printTree(tree[i]):'';
};
}(tree);
console.log(arr);

var obj ={first:"1",second:{name:"abc",mykey:"2",third:{age:"30",mykey:"3"}},forth:"4",mykey:"5"};console.log(getMykey(obj, []));functiongetMykey(obj, mykeyValues) {//没有则跳出if (!obj["mykey"]) {return mykeyValues;}else{//有就放入mykeyValues.push(obj["mykey"]);//再次递归var keys =Object.keys(obj);keys.forEach(function(i) {getMykey(obj[i], mykeyValues);});}return mykeyValues;}