Searching json array for a specific attribute

Based on your sample code what I understand you have is an array of objects and you want to find objects with one specific property and or value:

This will return true if the object has the property

var results= arr.filter(function(item){ return item.hasOwnProperty("column5");  });

Or you can perform additional action when you find the property:

arr.filter(function(item){ 
   if (item.hasOwnProperty("column5")) { 
        return item["column5"] === 'demo 01'; //or item.column5 === 'demo 01'
   } 
   return false;   
 });

• This only works on IE9+ if you need this to run in older versions of IE, please follow the instructions under polyfill:

  https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter

The you can check like

var obj = $.parseJSON(response);

$.each(obj, function (index,value) {

if(typeof obj[index].heading2 !== "undefined")
{
    alert(obj[index].heading2);
}

when in other object of array element not find then it returns undefined. and you can check like that.

you can check in this http://jsfiddle.net/gKRCH/

It's best to use a loop. But if the format of the JSON is regular, you could regex for the value in the response string.

I'm not recommending this method, just pointing out that it exists.

var value = "heading1";
if( (new RegExp('"' + value + '"')).test(response) ){
     // Found value
};

Here, we take the required value, wrap it in quotation marks and search for it in the response.

This has several issues, such as:

1. It might find the pattern in a property name
2. If the value could contain regex special characters, they'll need escaping.
3. If your JSON contains values with escaped quotation marks, you could get a false positive from partial matches.

That's why it depends on you knowing the format of the data.

EDIT:

You can solve issue 2 by using this condition instead of regex. But it gives you less flexibility.

response.indexOf('"' + value + '"') !== -1

Try this,

$.each(object,function(key, value){
console.log(key);
console.log(value);
});

You can use this JS lib; DefiantJS (http://defiantjs.com). This lib extends the global object JSON with the method "search" - with which, you can perform XPath queries on JSON structures. Like the one you have exemplified.

With XPath expressions (which is standardised query language), you can find whatever you're looking for and DefiantJS will do the heavy-lifting for you - allowing your code to be neat and clean.

Here is the fiddle of this code:
http://jsfiddle.net/hbi99/q8xst/

Here is the code:

    var data = [
       {
          "heading1": "heading1",
          "heading2": "heading2",
          "heading3": "heading3",
          "heading4": "heading4",
          "heading5": "heading5",
          "heading6": "heading6"
       },
       {
          "column1": 65536,
          "column2": "school",
          "column3": "testing purpose",
          "column4": "DESKTOP",
          "column5": "ACTIVE",
          "column6": true,
          "column7": "a6cc82e0-a8d8-49b8-af62-cf8ca042c8bb"
       },
       {
          "column1": 98305,
          "column2": "Nikhil",
          "column3": "Test",
          "column4": "LAPTOP",
          "column5": "ACTIVE",
          "column6": true,
          "column7": "a6cc82e0-a8d8-49b8-af62-cf8ca042c8bb"
       }
    ],
    res = JSON.search( data, '//*[column4="DESKTOP"]' );

console.log( res[0].column2 );
// school