angular.js - $http中的 for循环 Cannot read property 'menuName' of undefined

Question

$http.post('sysIndex/getSysIndexNameAndScoreByCid',{cid:id})
            .success(function(resp, status, headers, config){
                var index=resp.data                    
                for(var i=0;i<=index.length;i++){
                    var name=index[i].menuName;                                        
                }                  
            })

初学angular 为什么会报这个错

index的值是这样的。。

Answer 1

You need to set a breakpoint to see what the retrieved index is

---

I know, you wrote it while looping

for(var i=0;i<=index.length;i++)

should be

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

There is one more equal sign. So the last item is undefined, so there is no menuName attribute. . .

Answer 2

This is a problem with your background data.

Answer 3

The problem here should not be that every element under the index is undefined. In the screenshot of the questioner, only the first element is normal. Try changing it to the following:

var name = !!index[i]?index[i].menuName:'';