server.js

var http = require('http');

http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'application/json'});
    res.write('{"json":');
    if (Math.random() < 0.1) {
        // ??
    }
    res.write('"here"}');
    res.end();
}).listen(8124);