How to clear cache of service worker?

Question

So, I have an HTML page with service worker, the service worker cache the index.html and my JS files.

The problem is when I change the JS, the change doesn't show up directly on the client browser. Of course in chrome dev-tools, I can disable cache. But in chrome mobile, how do I do that?

I tried to access the site settings and hit the CLEAR % RESET button. But it still loads the old page/load from cache. I tried to use other browser or chrome incognito and it loads the new page.

Then, I try to clear my browsing data (just cache) and it works.

I guess that's not how it should work right? my user won't know if the page is updated without clearing the chrome browser cache.

Answer 1

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

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

Alternatively, to clear the cache for a PWA:

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

to list the names of the cache keys, then run:

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

to delete a cache key by name (i.e., 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:

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

I'm not convinced any of this will make it to spec.

Answer 2

Use this to delete outdated caches:

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);
        })
      );
    })
  );
});

Answer 3

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

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:

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