worker.ts

window.cacheUpdates = [];
window.channelInitialized = false;

export const initializeWorker = function() {
  if ('BroadcastChannel' in window) {
    // Subscribe to broadcast channel from worker
    const apiUpdates = new BroadcastChannel(BROADCAST_CHANNEL);
    apiUpdates.addEventListener('message', (event: any) => {
      if (window.channelInitialized) {
        return;
      }
      if (event.data.type === CACHE_UPDATED) {
        const { cacheName, updatedURL } = event.data.payload;
        console.log('W: worker append to cache updates', cacheName, updatedURL);
        window.cacheUpdates.push({
          cacheName, updatedURL
        });
      }
    });
  }
};