res.download(): Prompt a file to be downloaded.
res.end(): End the response process.
res.json(): Send a JSON response.
res.jsonp(): Send a JSON response with JSONP support.
res.redirect(): Redirect a request.
res.render(): Render a view template.
res.send(): Send a response of various types.
res.sendFile(): Send a file as an octet stream.
res.sendStatus(): Set the response status code and send its string representation as the response body.