fix(interface): fixes the storage interface to be async

The ThrottlerStorage interface now expects `getRecord` and `addRecord` to return promises, allowing
the methods to be called with `await`.

src/throttler-storage.interface.ts

@@ -1,6 +1,6 @@
 export interface ThrottlerStorage {
-  getRecord(key: string): number[];
-  addRecord(key: string, ttl: number): void;
+  getRecord(key: string): Promise<number[]>;
+  addRecord(key: string, ttl: number): Promise<void>;
 }
 
 export const ThrottlerStorage = Symbol('ThrottlerStorage');

src/throttler.guard.ts

@@ -47,7 +47,7 @@ export class ThrottlerGuard implements CanActivate {
     const req = context.switchToHttp().getRequest();
     const res = context.switchToHttp().getResponse();
     const key = md5(`${req.ip}-${classRef.name}-${handler.name}`);
-    const ttls = this.storageService.getRecord(key);
+    const ttls = await this.storageService.getRecord(key);
     const nearestExpiryTime = ttls.length > 0 ? Math.ceil((ttls[0] - Date.now()) / 1000) : 0;
 
     // Throw an error when the user reached their limit.
@@ -62,7 +62,7 @@ export class ThrottlerGuard implements CanActivate {
     res.header(`${headerPrefix}-Remaining`, Math.max(0, limit - (ttls.length + 1)));
     res.header(`${headerPrefix}-Reset`, nearestExpiryTime);
 
-    this.storageService.addRecord(key, ttl);
+    await this.storageService.addRecord(key, ttl);
     return true;
   }
 }

src/throttler.service.ts

@@ -5,11 +5,11 @@ import { ThrottlerStorage } from './throttler-storage.interface';
 export class ThrottlerStorageService implements ThrottlerStorage {
   storage: Record<string, number[]> = {};
 
-  getRecord(key: string): number[] {
+  async getRecord(key: string): Promise<number[]> {
     return this.storage[key] || [];
   }
 
-  addRecord(key: string, ttl: number): void {
+  async addRecord(key: string, ttl: number): Promise<void> {
     const ttlMilliseconds = ttl * 1000;
     if (!this.storage[key]) {
       this.storage[key] = [];