Javascript Object returns junk values

Question

I'm trying to assign values to a javascript object and when doing so, some junk values end up in there which seem like array methods like 'push', 'pop','splice' etc. The following is my code.

function myTest(){
var userArray = new Object();
var req = new Request.JSON({
url: '/myTest.php',
method: 'post',
noCache: true,
data: 'userID=999',

onSuccess: function(json){       
    for(var key in json){
      userArray = json[key];
      for (var row in userArray){
        alert(row)   // This returns values like '$family','push','pop', 'reverse' etc.
        }
    }
},
onException: function(xhr){
  alert("Unable to process your request");
},
onFailure: function(xhr){
  alert("Unable to connect to the server");
}
}).send();
}

I am not sure what I'm missing here but it looks like I certainly am. Any help on this would be greatly appreciated.

What you have posted there is a syntax error. Please post your actual code to avoid wasting everybody's time. — Pointy, Sep 05 '12 at 15:43
You can remove them by checking `if (json.hasOwnProperty(key))` inside your loop. — Matt, Sep 05 '12 at 15:45
Well it's still syntactically incorrect. It looks like a jumble of object literal notation and part of a function declaration. — Pointy, Sep 05 '12 at 15:57
@Pointy I'm not sure what's wrong here but that's all I have and I didn't want to paste the entire code which would be confusing. Thanks. — Nash3man, Sep 05 '12 at 16:21

score 3 · Accepted Answer · edited May 23 '17 at 12:20

3

Never use for...in on an array. Period. The garbage values you are seeing are properties of the array prototype.

See this related question.

edited May 23 '17 at 12:20

Community

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1

answered Sep 05 '12 at 15:45

jbabey

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Thank you jbabey. That was my bad to have missed it. This solved it. Appreciate your extremely quick response :) – Nash3man Sep 05 '12 at 15:51

score 1 · Answer 2 · answered Sep 05 '12 at 15:45

for (var row in userArray){
        if(userArray.hasOwnProperty(row))
           alert(row) ;  
        }

Details here. Basically, for loop will take all available properties/functions. And you must check if it belongs to that object only or is inherited.

Javascript Object returns junk values

2 Answers2

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