add CachedFetchValue overrides type (#727)

Author: dario-piotrowicz

.changeset/nasty-boats-boil.md

@@ -0,0 +1,5 @@
+---
+"@opennextjs/aws": patch
+---
+
+add and expose new `CachedFetchValue` type

packages/open-next/src/overrides/incrementalCache/multi-tier-ddb-s3.ts

@@ -50,9 +50,15 @@ const buildDynamoKey = (key: string) => {
  */
 const multiTierCache: IncrementalCache = {
   name: "multi-tier-ddb-s3",
-  async get(key, isFetch) {
+  async get<IsFetch extends boolean = false>(key: string, isFetch?: IsFetch) {
     // First we check the local cache
-    const localCacheEntry = localCache.get(key);
+    const localCacheEntry = localCache.get(key) as
+      | {
+          value: CacheValue<IsFetch>;
+          lastModified: number;
+        }
+      | undefined;
+
     if (localCacheEntry) {
       if (Date.now() - localCacheEntry.lastModified < localCacheTTL) {
         debug("Using local cache without checking ddb");

packages/open-next/src/types/overrides.ts

@@ -54,15 +54,29 @@ export type CachedFile =
       meta?: Meta;
     };
 
-export type FetchCache = Object;
+// type taken from: https://github.com/vercel/next.js/blob/9a1cd356/packages/next/src/server/response-cache/types.ts#L26-L38
+export type CachedFetchValue = {
+  kind: "FETCH";
+  data: {
+    headers: { [k: string]: string };
+    body: string;
+    url: string;
+    status?: number;
+    // field used by older versions of Next.js (see: https://github.com/vercel/next.js/blob/fda1ecc/packages/next/src/server/response-cache/types.ts#L23)
+    tags?: string[];
+  };
+  // tags are only present with file-system-cache
+  // fetch cache stores tags outside of cache entry
+  tags?: string[];
+};
 
 export type WithLastModified<T> = {
   lastModified?: number;
   value?: T;
 };
 
 export type CacheValue<IsFetch extends boolean> = (IsFetch extends true
-  ? FetchCache
+  ? CachedFetchValue
   : CachedFile) & { revalidate?: number | false };
 
 export type IncrementalCache = {