Iterating through javascript array using ranged for loop

Question

I have an MVC app where the controller takes a list of objects, serializes it using JavaScriptSerializer() creating a JSON object that is passed to the client side view.

For some reason, when I try to iterate through the object using a ranged for loop, each object is undefined, but when I iterate through the object with a regular for loop and index the object using the current iteration value in square brackets, I'm able to access each sub object (ie this works for(var i = 0; i < jsonObj.length; i++) vs this for(var sub in jsonObj) . Why doesn't the ranged for loop work in this instance?

JSON Object:

[
    "Obj1": {
            "Value1": "3454234",
            "Value2": "345643564",
            "Value3": "665445",
            "Value4": "True"
        },
        "Obj2": {
            "Value1": "3454234",
            "Value2": "345643564",
            "Value3": "665445",
            "Value4": "True"
        },
        "Obj3": {
            "Value1": "3454234",
            "Value2": "345643564",
            "Value3": "665445",
            "Value4": "True"
        }
]

EDIT

for(var sub in finalJson){
  console.log(sub["Value1"])
}

Answer 1

Your JSON is not valid, you either need to remove the object names so it's a valid list:

[{
   "Value1": "3454234",
   "Value2": "345643564",
   "Value3": "665445",
   "Value4": "True"
 }, {
   "Value1": "3454234",
   "Value2": "345643564",
   "Value3": "665445",
   "Value4": "True"
 } {
   "Value1": "3454234",
   "Value2": "345643564",
   "Value3": "665445",
   "Value4": "True"
 }]

in which case a ranged loop will work:

JsonObj.forEach(function(obj) {
   console.log(obj);
})

or convert it to an object containing the other objects as properties:

{
  "Obj1": {
    "Value1": "3454234",
    "Value2": "345643564",
    "Value3": "665445",
    "Value4": "True"
  },
  "Obj2": {
    "Value1": "3454234",
    "Value2": "345643564",
    "Value3": "665445",
    "Value4": "True"
  },
  "Obj3": {
    "Value1": "3454234",
    "Value2": "345643564",
    "Value3": "665445",
    "Value4": "True"
  }
}

in which case you can loop through via the keys:

for(var key in JsonObj) {
   console.log(key);
}

The reason your second loop wasn't working is because for..in is used to iterate through an objects keys, but your JSON is an array of objects, not an object

Answer 2

The JSON Object you've provide is not correct JSON object. It is an array of key-value pairs. Correct JSON object must be surrounded by { ... }, not by [ ... ]. You can check variable type jsonObj instanceof Array; If it gets true - then that is the reason.