In the Hello World example we used the Response.send() method to send a simple string as a response, and to close the connection:

(req, res) => res.send('Hello World!')

If you pass in a string, it sets the Content-Type header to text/html.

if you pass in an object or an array, it sets the application/json Content-Type header, and parses that parameter into JSON.

send() automatically sets the Content-Length HTTP response header.

send() also automatically closes the connection.

Use end() to send an empty response

An alternative way to send the response, without any body, it’s by using the Response.end() method:

res.end()

Set the HTTP response status

Use the Response.status():

res.status(404).end()

or

res.status(404).send('File not found')

sendStatus() is a shortcut:

res.sendStatus(200)
// === res.status(200).send('OK')

res.sendStatus(403)
// === res.status(403).send('Forbidden')

res.sendStatus(404)
// === res.status(404).send('Not Found')

res.sendStatus(500)
// === res.status(500).send('Internal Server Error')