CORS in an Express app.

app.js

app.use(function (req, res, next) {
    res.header('Access-Control-Allow-Origin', '*');
    res.header('Access-Control-Allow-Credentials', true);
    res.header('Access-Control-Allow-Methods',
         'GET,PUT,POST,DELETE,OPTIONS,HEAD');
    res.header('Access-Control-Allow-Headers', 'Content-Type');
    next();
});