res.json()

res.json([body])

Sends a JSON response. This method is identical to res.send() with an object or array as the parameter. However, you can use it to convert other values to JSON, such as null, and undefined (although these are technically not valid JSON).

res.json(null);
res.json({ user: 'tobi' });
res.status(500).json({ error: 'message' });