Javascript (jQuery) test for array in json object and return value

Question

UDPATE: SO WHATS THE BEST WAY TO ILLITERATE THROUGH A MULTI DIMENSIONAL ARRAY. SO CHECKING FOR OBJECTS INSIDE COMPLEX ARRAYS AND GRABBING THEIR VALUES.

{ "error":{
      "data": {
             "id":"3",
             "name":"404",
             "content" : "value"
       },
      "response":"Invalid path.",
      "code": 1
   }
}

if(json.error.data  !== undefined) {
      alert('value: ' + json.error.data);
}

I'm having an issue here; I can't seem to correctly resolved. When I try to check an array for a value it returns the error "Uncaught TypeError: Cannot read property 'data' of undefined" if the array data doesn't exist or content isn't present. I know there is a way to use indexOf() to test if the value is present, but this doesn't help me. I need to test for that value and then capture it. Remember, this is a multidimensional array so just using indexOf won't necessarily locate the complexity of the array and how to locate it.

Ok, so put simply. I need to say, does the array data and the parameter content exist in the error array shown above. If it does, then capture it's value and do something.

I also read about jQuery.inArray(); I don't know how to utilize this for complex multidimensional arrays.

Is the only successful way to do this using a loop for( x in z) {}

Answer 1

To test for undefined, use typeof and the string 'undefined'.

Also, check for the existence of the .error parent property of .data after parsing the string into JSON. It isn't clear from your code whether that has actually been done.

var obj = JSON.parse(json);

if (typeof obj.error !== 'undefined') {
  if(typeof obj.error.data  !== 'undefined') {
        alert('value: ' + obj.error.data);
  }
}

Answer 2

https://stackoverflow.com/a/2313663/528858

try{
   var json = JSON.parse(this.responseText);
}catch(e)
   alert('invalid json');
}

Answer 3

I think you got your object wrong.

json = '{...

You are starting with a single quote. Variable json is now a string, not a JavaScript object.

Answer 4

declare your object as this

json = 
{ 
    "error":{
        "data": {
            "id":"3",
            "name":"404",
            "content" : "value"
        },
        "response":"Invalid path.",
        "code": 1
    }
};

Answer 5

I think its as simple as the fact that you've surrounded your object with quotes, which makes its a string instead of an object. Remove those and it should work fine.