app.all('*', function (req, res, next) {

     res.header('Access-Control-Allow-Origin', '*');

     res.header('Access-Control-Allow-Headers', 'Content-Type, Content-Length, Authorization, Accept, X-Requested-With , yourHeaderFeild');

     res.header('Access-Control-Allow-Methods', 'PUT, POST, GET, DELETE, OPTIONS');

     if (req.method == 'OPTIONS') {

         res.send(200);

     } else {

         next();

     }

 });