How to clear cache of service worker?

清除Service Worker的缓存通常涉及以下几个步骤：

1. 注销Service Worker：

   • 打开浏览器的开发者工具。
   • 转到“Application”面板。
   • 在左侧边栏中找到“Service Workers”。
   • 点击“Unregister”以注销当前域名下的Service Worker。

2. 清除缓存：

   • 在相同的“Application”面板中，找到“Cache Storage”。
   • 展开“Cache Storage”部分，列出所有的缓存。
   • 右键点击需要删除的缓存，选择“Delete”来清除缓存。

3. 使用代码清除缓存： 可以在Service Worker的脚本中编写代码来清除缓存。例如：

   javascript
   self.addEventListener('activate', event => {
     event.waitUntil(
       caches.keys().then(cacheNames => {
         return Promise.all(
           cacheNames.map(cacheName => {
             // 假设'v1'是你想要保留的缓存的版本
             if (cacheName !== 'v1') {
               console.log('Service Worker: 清除旧缓存', cacheName);
               return caches.delete(cacheName);
             }
           })
         );
       })
     );
   });

   上述代码会在Service Worker激活时运行，它会遍历所有的缓存，并删除那些版本不是'v1'的缓存。

除了这些步骤，重要的是确保在更新Service Worker脚本后，让用户的浏览器获取到最新的Service Worker文件。通常，这可以通过更改Service Worker文件的内容来实现，因为浏览器会检查文件内容是否有变化来决定是否需要安装新的Service Worker。

例如，如果我刚完成一个项目，需要更新Service Worker以及对应的缓存，我会更新Service Worker脚本，可能是修改内部的缓存策略或者版本标签，然后将修改后的脚本部署到服务器。这样用户下次访问时，浏览器会检测到Service Worker脚本的内容更新，触发安装新的Service Worker，并在activate事件中清除旧的缓存。

总的来说，清除Service Worker的缓存需要综合运用开发者工具和编写Service Worker代码的方式来实现。这对于保持应用的性能和确保用户获得最新内容非常重要。

If you know the cache name you can simply call caches.delete() from anywhere you like in the worker:

shell
caches.delete(/*name*/);

And if you wanted to wipe all caches (and not wait for them, say this is a background task) you only need to add this:

shell
caches.keys().then(function(names) {
    for (let name of names)
        caches.delete(name);
});

Use this to delete outdated caches:

shell
self.addEventListener('activate', function(event) {
  event.waitUntil(
    caches.keys().then(function(cacheNames) {
      return Promise.all(
        cacheNames.filter(function(cacheName) {
          // Return true if you want to remove this cache,
          // but remember that caches are shared across
          // the whole origin
        }).map(function(cacheName) {
          return caches.delete(cacheName);
        })
      );
    })
  );
});

Typically you update the CACHE_NAME in your service workers JS file so your worker installs again:

shell
self.addEventListener('install', evt => {
  evt.waitUntil(
    caches.open(CACHE_NAME).then(cache => cache.addAll(inputs))
  )
})

Alternatively, to clear the cache for a PWA find the cache name:

shell
self.caches.keys().then(keys => { keys.forEach(key => console.log(key)) })

then run the following to delete it:

shell
self.caches.delete('my-site-cache')

Then refresh the page.

If you see any worker-related errors in the console after refreshing, you may also need to unregister the registered workers:

shell
navigator.serviceWorker.getRegistrations()
  .then(registrations => {
    registrations.forEach(registration => {
      registration.unregister()
    }) 
  })

The most elegant solution, with async/await:

shell
const cacheName = 'v2';

self.addEventListener('activate', event => {
// Remove old caches
  event.waitUntil(
    (async () => {
      const keys = await caches.keys();
      return keys.map(async (cache) => {
        if(cache !== cacheName) {
          console.log('Service Worker: Removing old cache: '+cache);
          return await caches.delete(cache);
        }
      })
    })()
  )
})

This is the only code that worked for me. It is my adaptation of Mozilla documentation :

shell
//Delete all caches and keep only one
const cachNameToKeep = 'myCache';

//Deletion should only occur at the activate event
self.addEventListener('activate', event => {
    var cacheKeeplist = [cacheName];
    event.waitUntil(
        caches.keys().then( keyList => {
            return Promise.all(keyList.map( key => {
                if (cacheKeeplist.indexOf(key) === -1) {
                    return caches.delete(key);
                }
            }));
        })
.then(self.clients.claim())); //this line is important in some contexts
});