code: function applyEventStrategy(strategy, event) {
    const request = event.request;
    switch (strategy.type) {
      case 'offline-only':
        return fetchAndCache(request, strategy)().catch(getFromCache(request));
      case 'fallback-only':
        return fetchAndCache(request, strategy)().then(fallbackToCache(request));
      case 'prefer-cache':
        return getFromCache(request)().catch(fetchAndCache(request, strategy));
      case 'race':
        return getFromFastest(request, strategy)();
      default:
        return Promise.reject(`Strategy not supported: ${strategy.type}`);
    }
  }
docs: /*         -------- CACHE HELPERS ---------