Express 5 cheatsheet

Express 5: Error handling

3 common Express 5 tasks.

Handle errors in async routes

In Express 5, a rejected promise or thrown error in an async handler is passed to the error handler automatically.

app.get("/users/:id", async (req, res) => {
  const user = await db.findUser(req.params.id);
  res.json(user);
});

Define it last. It takes four arguments.

app.use((err, req, res, next) => {
  console.error(err);
  res.status(500).json({ error: "Internal Server Error" });
});

Add a catch-all after your routes.

app.use((req, res) => {
  res.status(404).json({ error: "Not found" });
});