在我的服务工作者我存储mp4视频在indexedDB与本地搜索库在一个blob数据。它的工作！但我不知道如何才能返回这个blob数据。
下面是我的fetchHandler代码：

const fetchHandler = async (event) => {
    const getResponse = async () => {
        const request = event.request;
        if( request.destination === 'video' ){
            // Get from indexedDB
            const value = await localforage.getItem('video');
            // How return the video from indexedDB cache ?
            if( value ) return value; // not working
            // Add in indexedDB
            var networkResponse = await fetch(event.request);
            localforage.setItem('video', networkResponse.blob() ).then(function (value) {
                // Do other things once the value has been saved.
                console.log(value);
            }).catch(function(err) {
                // This code runs if there were any errors
                console.log(err);
            });
        }else{
            const openedCache = await caches.open(SW_CACHE_NAME);
            const cacheResponse = await openedCache.match(request);
            if (cacheResponse) return cacheResponse;

            var networkResponse = await fetch(event.request);
            const cachePutResponse = await openedCache.put(request, networkResponse.clone());
            if (cachePutResponse) return cachePutResponse;
        }

        return networkResponse;
    };
    event.respondWith(getResponse());
};

谢谢你的帮助