如何从Service Worker发送“离线”消息？

Question

如何返回缓存并带有离线消息？这可行吗？

我目前的代码只是简单地返回缓存：

const cachedFetch = request => request.method != 'GET' ? 

  fetch(request) : 
  caches.open("demo").then(cache =>
    cache.match(request).then(resp => {
      if(!!resp) {
        console.log('cache', request.url)
        return resp;// how to send custom message back with resp
      } else {
        console.log('not in cache', request.url)
        return fetch(request).then(response => {
         return response


        })
      }
    })
  )

self.addEventListener('fetch', event => event.respondWith(
    cachedFetch(event.request)
  )
)

- Tommy

Answer 1

Service Worker 可以使用 postMessage() 通知客户端。此外，应用程序也可以独立于 Service Worker 监听在线/离线事件：

https://developer.mozilla.org/en-US/docs/Web/API/NavigatorOnLine/Online_and_offline_events

- anthumchris