sw.js

"use strict"


const CACHE_NAME = 'service-cache-by-test';
const urlToCache =[
    '/',
    '/styles/main.css',
    '/script/main.js'
]

// 安装事件
self.addEventListener('install',function(event){
  event.waitUntil(
    caches.open(CACHE_NAME).then(function(cache){
        console.log('Opened cache')
        return cache.addAll(urlToCache)
    })
  )
})
self.addEventListener('fetch', function(event) {
  event.respondWith(
    caches.match(event.request)
      .then(function(response) {
        // Cache hit - return response
        if (response) {
          return response;
        }
        return fetch(event.request);
      }
    )
  );
});
// 
self.addEventListener('activate', event => {
    console.log('V1 now ready to handle fetches!');
    // 这里是更新
  });

//   // 判断是否跨域了
// const isCORSRequest = function(url, host) {
//     return url.search(host) === -1;
// };
// const isValidResponse = function(response) {
// 	return response && response.status >= 200 && response.status < 400 && response.type !== 'basic'
// };

// const HOST_NAME = location.host;
// console.log(location.host)

// const handleFetchRequest = function(req) {
//   const newRequest = isCORSRequest(req.url, HOST_NAME) ? new Request(req.url, {mode: 'cors'}) :req;
//   return caches.match(newRequest).then(function(response) {
//       // Cache hit - return response
//       if (response) {
//         return response;
//       }

//       const fetchRequest = newRequest.clone();
//       return fetch(fetchRequest)
//         .then(function(response) {
//           // Check if we received an valid response
//           if (isValidResponse(response)) {
//             const responseToCache = response.clone();
//             caches.open(CACHE_NAME).then(function(cache) {
//                 cache.put(newRequest, responseToCache);
//               });
//           }

//           return response;
//         });
//     });

// };

// const onFetch = function(event) {
// 	event.respondWith(handleFetchRequest(event.request));
// };
// // 更新事件
// self.addEventListener('fetch', onFetch);