To retrieve data from MongoDB, you use methods provided by the model.

To get all documents:

app.get('/users', async (req, res) => {
  const users = await User.find();

  res.json(users);
});

To get a single document by id:

app.get('/users/:id', async (req, res) => {
  const user = await User.findById(req.params.id);

  res.json(user);
});

Examples:

• '/users': returns all users;
• '/users/123': returns user with id 123.

These methods allow your API to read data from the database and return it to the client.