How do I check Content-Type using ExpressJS?

If you’re using Express 4.0 or higher, you can call request.is() on requests from your handlers to filter request content type. For example:

app.use('/api/', (req, res, next) => {
    if (!req.is('application/json')) {
        // Send error here
        res.send(400);
    } else {
        // Do logic here
    }
});