Function insert

lib/internal/timers.js:387–408

(item, msecs, start = binding.getLibuvNow())

// We need to use the binding as the receiver for fast API calls.
function insert(item, msecs, start = binding.getLibuvNow()) {
  // Truncate so that accuracy of sub-millisecond timers is not assumed.
  msecs = MathTrunc(msecs);
  item._idleStart = start;

  // Use an existing list if there is one, otherwise we need to make a new one.
  let list = timerListMap[msecs];
  if (list === undefined) {
    debug('no %d list was found in insert, creating a new one', msecs);
    const expiry = start + msecs;
    timerListMap[msecs] = list = new TimersList(expiry, msecs);
    timerListQueue.insert(list);

    if (nextExpiry > expiry) {
      // We need to use the binding as the receiver for fast API calls.
      binding.scheduleTimer(msecs);
      nextExpiry = expiry;
    }
  }

  L.append(list, item);
}

function setUnrefTimeout(callback, after) {
  // Type checking identical to setTimeout()