created dedicated fixed window type

Author: shalarewicz

src/@types/rateLimit.d.ts

@@ -24,11 +24,13 @@ export interface RedisBucket {
     timestamp: number;
 }
 
-export interface RedisWindow {
+export interface FixedWindow {
     currentTokens: number;
-    previousTokens: number;
     fixedWindowStart: number;
 }
+export interface RedisWindow extends FixedWindow {
+    previousTokens: number;
+}
 
 export type RedisLog = RedisBucket[];
 

src/rateLimiters/fixedWindow.ts

@@ -1,5 +1,5 @@
 import Redis from 'ioredis';
-import { RateLimiter, RateLimiterResponse, RedisWindow } from '../@types/rateLimit';
+import { RateLimiter, RateLimiterResponse, FixedWindow as Window } from '../@types/rateLimit';
 
 /**
  * The FixedWindow instance of a RateLimiter limits requests based on a unique user ID and a fixed time window.
@@ -69,7 +69,7 @@ class FixedWindow implements RateLimiter {
         const windowJSON = await this.client.get(uuid);
 
         if (windowJSON === null) {
-            const newUserWindow: RedisWindow = {
+            const newUserWindow: Window = {
                 currentTokens: tokens > this.capacity ? 0 : tokens,
                 fixedWindowStart: timestamp,
             };
@@ -81,7 +81,7 @@ class FixedWindow implements RateLimiter {
             await this.client.setex(uuid, keyExpiry, JSON.stringify(newUserWindow));
             return { success: true, tokens: this.capacity - newUserWindow.currentTokens };
         }
-        const window: RedisWindow = await JSON.parse(windowJSON);
+        const window: Window = await JSON.parse(windowJSON);
 
         const updatedUserWindow = this.updateTimeWindow(window, timestamp);
         updatedUserWindow.currentTokens += tokens;
@@ -113,8 +113,8 @@ class FixedWindow implements RateLimiter {
         this.client.flushall();
     }
 
-    private updateTimeWindow = (window: RedisWindow, timestamp: number): RedisWindow => {
-        const updatedUserWindow: RedisWindow = {
+    private updateTimeWindow = (window: Window, timestamp: number): Window => {
+        const updatedUserWindow: Window = {
             currentTokens: window.currentTokens,
             fixedWindowStart: window.fixedWindowStart,
         };

test/rateLimiters/fixedWindow.test.ts

@@ -1,5 +1,5 @@
 import * as ioredis from 'ioredis';
-import { RedisWindow } from '../../src/@types/rateLimit';
+import { FixedWindow as Window } from '../../src/@types/rateLimit';
 import FixedWindow from '../../src/rateLimiters/fixedWindow';
 
 // eslint-disable-next-line @typescript-eslint/no-var-requires
@@ -15,7 +15,7 @@ const user1 = '1';
 const user2 = '2';
 const user3 = '3';
 
-async function getWindowFromClient(redisClient: ioredis.Redis, uuid: string): Promise<RedisWindow> {
+async function getWindowFromClient(redisClient: ioredis.Redis, uuid: string): Promise<Window> {
     const res = await redisClient.get(uuid);
     // if no uuid is found, return -1 for tokens and timestamp, which are both impossible
     if (res === null) return { currentTokens: -1, fixedWindowStart: -1 };
@@ -28,7 +28,7 @@ async function setTokenCountInClient(
     currentTokens: number,
     fixedWindowStart: number
 ) {
-    const value: RedisWindow = { currentTokens, fixedWindowStart };
+    const value: Window = { currentTokens, fixedWindowStart };
     await redisClient.set(uuid, JSON.stringify(value));
 }
 describe('Test FixedWindow Rate Limiter', () => {