RateLimiterQueue

RateLimiterQueue is a lightweight, TypeScript-based rate limiter designed to help manage API requests in a queue, ensuring that no more than a specified number of requests are processed per minute. The class makes it easy to handle large volumes of requests without breaching rate limits.

Features

• Enqueue Requests: Queue up requests and ensure they are processed at a controlled rate.
• Request Limits: Set a maximum number of requests per minute to comply with API rate limits.
• Automatic Cleanup: Old request timestamps are periodically removed to maintain accurate rate limiting.
• Error Handling: Each request in the queue can fail independently without affecting other requests.
• Batch Processing: Enqueue an array of requests to be processed with a single call.

Installation

To install this package, use npm:

npm install rate-limiter-queue

Usage

Importing and Instantiation

import RateLimiterQueue from 'rate-limiter-queue';

const rateLimiter = new RateLimiterQueue(60); // Limit to 60 requests per minute

Enqueuing Requests

The enqueue method allows you to add requests to the queue. Each request will be processed according to the rate limit.

const fetchData = async () => {
  // Your async operation, e.g., fetch or axios call
};

rateLimiter.enqueue(fetchData).then((response) => {
  console.log("Request completed:", response);
}).catch((error) => {
  console.error("Request failed:", error);
});

Batch Processing

The processAll method allows you to process multiple requests at once, adhering to the rate limit:

const requests = [
  async () => await fetchData(),
  async () => await fetchData(),
  // More request functions
];

rateLimiter.processAll(requests).then((results) => {
  console.log("All requests completed:", results);
}).catch((error) => {
  console.error("Error processing batch:", error);
});

API

Constructor

new RateLimiterQueue(maxRequestsPerMinute: number)

• maxRequestsPerMinute: Maximum number of requests allowed per minute.

Methods

• enqueue(requestFunction: () => Promise): Promise
  Adds a request function to the queue. Returns a promise that resolves with the request's result.

• processAll(requestFunctions: Array<() => Promise>): Promise<T[]>
  Accepts an array of request functions to process as a batch, adhering to the rate limit. Returns a promise that resolves with an array of results.

Example

const rateLimiter = new RateLimiterQueue(10); // 10 requests per minute

const requests = Array.from({ length: 15 }, (_, i) => async () => {
  console.log(`Processing request ${i + 1}`);
  await new Promise(resolve => setTimeout(resolve, 100)); // Simulate delay
});

rateLimiter.processAll(requests).then(results => {
  console.log("Finished processing all requests.");
});

License

MIT