fixup! client: Add more type annotations

client/selfoss-sw-offline.ts

@@ -1,45 +1,50 @@
 /* eslint-env worker, serviceworker */
+/// <reference lib="WebWorker" />
 
 import { manifest, version } from '@parcel/service-worker';
 
-async function install() {
+// Default type of `self` is `WorkerGlobalScope & typeof globalThis`
+// https://github.com/microsoft/TypeScript/issues/14877
+declare const self: ServiceWorkerGlobalScope;
+
+async function install(): Promise<undefined> {
     const cache = await caches.open(version);
 
-    const entriesToCache =
+    const entriesToCache: string[] =
         manifest
             // We need to pass index.html through PHP to perform templating.
-            .map((entry) => entry === 'index.html' ? './' : entry);
+            .map((entry: string) => entry === 'index.html' ? './' : entry);
 
     await cache.addAll(entriesToCache);
 }
-self.addEventListener('install', (event) => event.waitUntil(install()));
+self.addEventListener('install', (event: ExtendableEvent) => event.waitUntil(install()));
 
 
-async function activate() {
+async function activate(): Promise<Array<boolean>> {
     const keys = await caches.keys();
     await Promise.all(
         keys
-            .filter((key) => !(key === version || key === 'userCss' || key === 'userJs'))
-            .map((key) => caches.delete(key))
+            .filter((key: string) => !(key === version || key === 'userCss' || key === 'userJs'))
+            .map((key: string) => caches.delete(key))
     );
 }
-self.addEventListener('activate', (event) => event.waitUntil(activate()));
+self.addEventListener('activate', (event: ExtendableEvent) => event.waitUntil(activate()));
 
 
-self.addEventListener('fetch', (event) => {
+self.addEventListener('fetch', (event: FetchEvent) => {
     if (event.request.method !== 'GET' || event.request.headers.get('X-Requested-With') === 'XMLHttpRequest') {
         return;
     }
 
     event.respondWith(
         caches.match(event.request)
-            .then((cachedResponse) => cachedResponse || fetch(event.request))
+            .then((cachedResponse: Response | undefined) => cachedResponse || fetch(event.request))
             .catch(() => caches.match('./'))
     );
 });
 
 
-self.addEventListener('message', (messageEvent) => {
+self.addEventListener('message', (messageEvent: ExtendableMessageEvent) => {
     if (messageEvent.data === 'skipWaiting') {
         return self.skipWaiting();
     }