lastcall

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Getting Started ​

Published on npm as lastcall. Repository: github.com/sakurablush/lastcall. Docs: sakurablush.github.io/lastcall.

Install ​

bash
npm install lastcall

Requires Node.js 18+. Works with Bun (see Bun guide).

Minimal example ​

ts
import { createServer } from 'node:http';
import { createLastcall } from 'lastcall';

const server = createServer((req, res) => {
  res.end('ok');
});

const lastcall = createLastcall();

// 1. Drain HTTP connections (phase: drain) — register before listen()
lastcall.withHttpServer(server);

// 2. Close infrastructure (phase: cleanup)
lastcall.register(
  'database',
  async () => {
    await db.disconnect();
  },
  { critical: true },
);

// 3. Optional: stop accepting new work (phase: pre)
let acceptingWork = true;
lastcall.register(
  'health',
  async () => {
    acceptingWork = false;
  },
  { phase: 'pre' },
);

server.listen(3000);

When the process receives SIGTERM (Kubernetes, Docker) or Ctrl+C (SIGINT), lastcall runs your handlers in phase order:

  1. pre — handlers you register (e.g. flip health checks)
  2. drain — withHttpServer() and other drain handlers
  3. cleanup — databases, queues, caches
  4. post — final metrics or logs

Then it calls process.exit(0) — or 1 if a critical handler failed.

Nothing happens automatically unless you register it. withHttpServer() is the built-in drain helper; health checks and DB closes are yours to register.

Manual shutdown ​

ts
await lastcall.shutdown('maintenance');

Testing in your app ​

ts
const lastcall = createLastcall({
  autoExit: false, // don't call process.exit() in tests
  signals: [], // don't register OS signal listeners
});

lastcall.register('cleanup', vi.fn());
await lastcall.shutdown('test');

Use simulateSignal('SIGTERM') to test signal paths without sending real OS signals.

Use resetDefaultLastcall() when your tests call getDefaultLastcall() and need a fresh singleton between cases.

Health checks ​

ts
app.get('/health', (_req, res) => {
  if (lastcall.isShuttingDown()) {
    res.status(503).send('shutting down');
    return;
  }
  res.status(200).send('ok');
});

Pair with a pre phase handler that flips internal state if you need to stop accepting work before drain begins.

Next steps ​