Method onSnapshot

tracker/src/loop.ts:194–198

(now: number, aircraft: Aircraft[])

  // --- events from upstream / UI ---

  onSnapshot(now: number, aircraft: Aircraft[]): void {
    for (const ac of aircraft) this.history.observe(ac, now);
    this.history.prune(now);
    this.recorder.write("snapshot", { aircraft });
  }

  onConfig(config: Config): void {
    this.rescheduleTick();