I'm creating a NodeJS backend using Express, and I'm getting the following error: `Uncaught TypeError: Cannot read properties of undefined (reading 'id')` My code of where this error is happening is as follows: ``` app.delete('/post', (req, res) => { const user = getUser(req.user.user_id); if (!user) return res.sendStatus(401); const post = getPost(req.body.id); if (!post) return res.sendStatus(404); if (post.user_id != req.user.user_id) return res.sendStatus(403); // Code that deletes the post through DB return res.sendStatus(201); }); ``` What are ways I can fix this error?