use waitUntil for non-blocking cache

Author: 6

src/cache.ts

@@ -73,8 +73,6 @@ export class ResponseCache {
     response: Response;
     ttl: number | null;
   }): Promise<void> => {
-    // TODO: might be able to do ctx.waitUntil:
-    // https://developers.cloudflare.com/workers/examples/cache-api
     const body = await response.clone().text();
     const responseObject = {
       status: response.status,

src/proxy.ts

@@ -12,6 +12,7 @@ interface HandleProxyOpts {
 export const handleProxy = async ({
   request,
   env,
+  ctx,
   ttl,
   pathname,
 }: HandleProxyOpts): Promise<Response> => {
@@ -50,11 +51,13 @@ export const handleProxy = async ({
 
   if (response.ok) {
     console.log('Writing 2xx response to cache: ', { cacheKey, ttl });
-    await responseCache.write({
+    const writeCachePromise = responseCache.write({
       cacheKey,
       ttl,
       response,
     });
+    // https://developers.cloudflare.com/workers/runtime-apis/fetch-event/#waituntil
+    ctx.waitUntil(writeCachePromise);
   } else {
     console.log('Not caching error or empty response.');
   }