Why does a Node timeout scheduled for thirty days fire almost immediately?

Node sets a timeout delay above 2,147,483,647 milliseconds to 1 millisecond. Thirty days exceeds that documented limit; a large future date is not a valid single timer duration. Validate converted units, finite numbers and the maximum delay before scheduling. For a distant deadline, store its absolute due time and schedule bounded wake-ups that recompute the remaining duration. Only perform the action once the due time has actually arrived. Test a thirty-day input through the validation path without waiting thirty days, and test clock changes with an injected clock. A timer also disappears when its process stops: durable reminders require persisted state and restart reconciliation. This range failure differs from ordinary event-loop delay, which makes a valid timer run late rather than collapsing a huge delay to 1. Minimal example:

import assert from 'node:assert/strict';
function timerChunk(dueAt, now) {
  const remaining = dueAt - now;
  if (!Number.isFinite(remaining)) throw new TypeError('Invalid deadline');
  return Math.max(1, Math.min(remaining, 2_147_483_647));
}
const thirtyDays = 30 * 24 * 60 * 60 * 1000;
assert.equal(timerChunk(thirtyDays, 0), 2_147_483_647);
assert.equal(timerChunk(thirtyDays, thirtyDays - 25), 25);
assert.throws(() => timerChunk(NaN, 0), TypeError);
// Each wake-up must recheck the due time before performing the actual action.