diff --git a/engine/lib/cache.ts b/engine/lib/cache.ts
index c189d22..af9e6f5 100644
--- a/engine/lib/cache.ts
+++ b/engine/lib/cache.ts
@@ -1,4 +1,10 @@
-export type Cache<T> = Map<unknown, T>;
+export type Cache<T> = {
+	clear(): void;
+	delete(key: unknown): boolean;
+	get(key: unknown): T | undefined;
+	has(key: unknown): boolean;
+	set(key: unknown, value: T): unknown;
+};
 
 export function withCache<T, U extends (...args: Parameters<U>) => T>(
 	fn: U,