onShutdown() & close()

onShutdown()

Signature

app.onShutdown(fn)

Parameters

Name	Type	Description
fn	Function	Cleanup function (sync or async).

Returns: app (for chaining).

Example

app.onShutdown(async () => {
  await db.disconnect();
  console.log("Database closed");
});

// Chaining
app
  .onShutdown(() => db.disconnect())
  .onShutdown(() => cache.close())
  .start(3000);

Hooks run sequentially in registration order. If one throws, remaining hooks still execute.

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close()

Signature

// Promise API
await app.close();

// Callback API
app.close(callback);

Parameters

Name	Type	Description
callback	Function	Optional. Called with (err) when shutdown completes.

Returns:

• Without callback: Promise<void>
• With callback: app

Behavior

1. Stops the server from accepting new connections
2. Drains existing requests (up to configured timeout)
3. Runs all registered onShutdown hooks
4. Resolves / calls callback

Safe to call multiple times — second call resolves immediately (idempotent).

Example

// Programmatic shutdown in tests
afterAll(async () => {
  await app.close();
});

// Callback style
app.close((err) => {
  if (err) console.error("Shutdown error:", err);
  process.exit(err ? 1 : 0);
});