Handling Errors in Express

Errors can happen when something goes wrong, such as invalid input or missing data.

In Express, you can send error responses using the response object.

app.get('/users/:id', (req, res) => {
  const id = Number(req.params.id);

  const user = users.find(u => u.id === id);

  if (!user) {
    return res.status(404).send('user not found');
  }

  res.json(user);
});

Here, if the user is not found, the server sends a response with a status code and a message.

Status codes help indicate what happened:

• 200: success;
• 404: resource not found;
• 500: server error.

Handling errors properly makes your API more predictable and easier to use.