Timers and handles

Node’s event loop stays alive while handles exist: timers, open sockets, fs watchers, etc.

Broken code

examples/node/04-timer-handle-leak.js — nested intervals without cleanup.

Fixed code

examples/node/04-timer-handle-fixed.js — store interval id, clearInterval on shutdown.

Graceful shutdown pattern

const timers = [];

function track(id) {
  timers.push(id);
  return id;
}

function shutdown() {
  for (const id of timers) clearInterval(id);
  server.close();
}

process.on('SIGTERM', shutdown);

Run it

node examples/node/04-timer-handle-leak.js
node examples/node/04-timer-handle-fixed.js