Refactor, cleanup

lib/memory_cache.test.ts

@@ -4,11 +4,13 @@ import { assertEquals } from "@std/assert";
 
 Deno.test("Memory cache", async () => {
   let calls = 0;
+
   async function expensiveFunction(key: string) {
     calls++;
     await sleep(1);
     return key;
   }
+
   assertEquals("key", await ttlCache("key", expensiveFunction, 0.01));
   assertEquals(1, calls);
   assertEquals("key", await ttlCache("key", expensiveFunction, 0.01));