Express: Send a response to the client

In the Hello World example we used the send() method of the Response object 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.

After this, send() closes the connection.

send() automatically sets the Content-Length HTTP response header, unlike end() which requires you to do that.

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 status() method on the response object:

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')

Lessons in this unit:

0: Introduction
1: Introduction to Express
2: Request parameters
3: ▶︎ Send a response to the client
4: Send a JSON response
5: Manage cookies
6: Work with HTTP headers
7: Handling redirects
8: Routing
9: Template engines
10: Middleware
11: Serving Static Assets with Express
12: Send files to the client
13: Sessions
14: Validating and sanitizing input
15: Handling form data
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