fix(service-worker): clean up caches from old SW versions (#26319)

Since the SW immediately takes over all clients, it is safe to delete
caches used by older (e.g. beta) `@angular/service-worker` versions to
avoid running into browser storage quota limitations.

PR Close #26319

packages/service-worker/worker/src/driver.ts

@@ -123,9 +123,22 @@ export class Driver implements Debuggable, UpdateSource {
     // The activate event is triggered when this version of the service worker is
     // first activated.
     this.scope.addEventListener('activate', (event) => {
-      // As above, it's safe to take over from existing clients immediately, since
-      // the new SW version will continue to serve the old application.
-      event !.waitUntil(this.scope.clients.claim());
+      event !.waitUntil((async() => {
+        // As above, it's safe to take over from existing clients immediately, since the new SW
+        // version will continue to serve the old application.
+        await this.scope.clients.claim();
+
+        // Once all clients have been taken over, we can delete caches used by old versions of
+        // `@angular/service-worker`, which are no longer needed. This can happen in the background.
+        this.idle.schedule('activate: cleanup-old-sw-caches', async() => {
+          try {
+            await this.cleanupOldSwCaches();
+          } catch (err) {
+            // Nothing to do - cleanup failed. Just log it.
+            this.debugger.log(err, 'cleanupOldSwCaches @ activate: cleanup-old-sw-caches');
+          }
+        });
+      })());
 
       // Rather than wait for the first fetch event, which may not arrive until
       // the next time the application is loaded, the SW takes advantage of the
@@ -872,6 +885,19 @@ export class Driver implements Debuggable, UpdateSource {
     await this.sync();
   }
 
+  /**
+   * Delete caches that were used by older versions of `@angular/service-worker` to avoid running
+   * into storage quota limitations imposed by browsers.
+   * (Since at this point the SW has claimed all clients, it is safe to remove those caches.)
+   */
+  async cleanupOldSwCaches(): Promise<void> {
+    const cacheNames = await this.scope.caches.keys();
+    const oldSwCacheNames =
+        cacheNames.filter(name => /^ngsw:(?:active|staged|manifest:.+)$/.test(name));
+
+    await Promise.all(oldSwCacheNames.map(name => this.scope.caches.delete(name)));
+  }
+
   /**
    * Determine if a specific version of the given resource is cached anywhere within the SW,
    * and fetch it if so.