`app.patch()`

Routes HTTP PATCH requests for a path, typically for partial updates.

Since Express 4 Spec ↗

Syntax

app.patch(path, ...handlers)

Parameters

Name	Type	Required	Description
`path`	`string \| RegExp`	Yes	The route path.
`handlers`	`...function`	Yes	The handler chain.

Returns

Application — The app instance, for chaining.

Examples

app.use(express.json());

app.patch('/users/:id', (req, res) => {
  const user = patchUser(req.params.id, req.body);
  res.json(user);
});

Output

$ curl -X PATCH -d '{"email":"a@b.co"}' -H 'Content-Type: application/json' localhost:3000/users/1
{"id":"1","name":"Ada","email":"a@b.co"}

app.patch('/posts/:id/publish', (req, res) => {
  publish(req.params.id);
  res.sendStatus(200);
});

Output

(200 OK)

Notes

PATCH applies a partial modification - only send changed fields. Unlike PUT it is not required to be idempotent. Whitelist allowed fields server-side to prevent mass-assignment vulnerabilities.