conversion of text file to json format in nodejs?

How can i Convert Text file data to Json format using nodeJS.

as i am new to NodeJS i want to convert a normal text file to json formatted file. can you please provide any links or examples please/

    var fs = require('fs');
console.log('starting');
var contents = fs.readFileSync('files/config.json');
console.log('contents'+contents);
console.log('c'+contents.username);

This code for normal retrieving data but i want a text file to json

via riza