Feat: new fs memo cache

Build/lib/fs-memo.ts

@@ -0,0 +1,51 @@
+import path from 'node:path';
+import { Cache } from './cache-filesystem';
+import type { CacheApplyOption } from './cache-filesystem';
+import { isCI } from 'ci-info';
+
+const fsMemoCache = new Cache({ cachePath: path.resolve(__dirname, '../../.cache') });
+
+const TTL = isCI
+  // We run CI daily, so 1.5 days TTL is enough to persist the cache across runs
+  ? 1.5 * 86400 * 1000
+  // We run locally less frequently, so we need to persist the cache for longer, 7 days
+  : 7 * 86400 * 1000;
+
+  type JSONValue =
+    | string
+    | number
+    | boolean
+    | null
+    | JSONObject
+    | JSONArray;
+
+interface JSONObject {
+  [key: string]: JSONValue
+}
+
+interface JSONArray extends Array<JSONValue> {}
+
+export function cache<Args extends JSONValue[], T>(
+  cb: (...args: Args) => Promise<T>,
+  opt: Omit<CacheApplyOption<T, string>, 'ttl'>
+): (...args: Args) => Promise<T> {
+  // TODO if cb.toString() is long we should hash it
+  const fixedKey = cb.toString();
+
+  return async function cachedCb(...args: Args) {
+    // Construct the complete cache key for this function invocation
+    // TODO stringify is limited. For now we uses typescript to guard the args.
+    const cacheKey = `${fixedKey}|${JSON.stringify(args)}`;
+    const cacheName = cb.name || cacheKey;
+
+    return fsMemoCache.apply(
+      cacheKey,
+      cb,
+      {
+        cacheName,
+        ...opt,
+        ttl: TTL
+      } as CacheApplyOption<T, string>
+    );
+  };
+}