json parse if json code example

Example 1: javascript is valid json string

function isValidJSONString(str) {
    try {
        JSON.parse(str);
    } catch (e) {
        return false;
    }
    return true;
}
//usage
var personJSONString = '{"first_name":"Tony","last_name":"Hawk","age":31}';
if(isValidJSONString(personJSONString)){
 //cool we are valid, lets parse
 var person= JSON.parse(personJSONString);
}

Example 2: json parse returns object

var str = '[{"UserName":"xxx","Rolename":"yyy"}]'; // your response in a string
    var parsed = JSON.parse(str); // an *array* that contains the user
    var user = parsed[0];         // a simple user
    console.log(user.UserName);   // you'll get xxx
    console.log(user.Rolename);   // you'll get yyy