Serializing objects into the JSON format in JavaScript

The JSON.stringify() method does the convertion of a JavaScript object into a JSON-formatted string.

JSON.stringify() is a function filters and transform the way a value is stringified

EXAMPLE:

var scores = { "Dhoni": 70, "Dhavan": 80, "Ashwin": 30 };  

var passed = JSON.stringify(scores, function (key, value) {
       if (value < 40) {
          return undefined;
       } else {
          return value;
       }
});

alert(passed);   // {"Dhoni":70,"Dhavan":80}