refactor: add typescript support to project

src/types/global.d.ts

@@ -1,8 +1,10 @@
 import { PrecacheEntry } from "workbox-precaching/src/_types";
+import localforage from "localforage";
 
 export declare global {
   interface Window {
     __WB_MANIFEST: Array<PrecacheEntry | string>;
     skipWaiting: () => void;
+    CACHE: { [key: string]: typeof localforage };
   }
 }