README

js-counter

Distributed rate limiting using Redis.

Supported Redis clients: node-redis v3 and v4, ioredis v4.

import { promisify } from 'util';
import { createClient } from 'redis';
import { createLimiter } from '@da440dil/js-counter';

const sleep = promisify(setTimeout);

async function main() {
    const client = createClient();
    await client.connect();

    // Create limiter with 2 limits.
    const limiter = createLimiter(
        client,
        // First limit: no more than 3 limiter calls within 1 second.
        { size: 1000, limit: 3 },
        // Second limit: no more than 5 limiter calls within 2 seconds.
        { size: 2000, limit: 5 }
    );

    const key = 'key';
    const limit = async (): Promise<void> => {
        const result = await limiter.limit(key);
        console.log(
            'Result: { ok: %s, counter: %d, remainder: %d, ttl: %d }',
            result.ok, result.counter, result.remainder, result.ttl
        );
    };

    await Promise.all([limit(), limit(), limit(), limit()]);
    await sleep(1000); // wait for the next window to start
    await Promise.all([limit(), limit()]);
    // Output:
    // Result: { ok: true, counter: 1, remainder: 2, ttl: -1 }
    // Result: { ok: true, counter: 2, remainder: 1, ttl: -1 }
    // Result: { ok: true, counter: 3, remainder: 0, ttl: -1 }
    // Result: { ok: false, counter: 3, remainder: 0, ttl: 1000 }
    // Result: { ok: true, counter: 5, remainder: 0, ttl: -1 }
    // Result: { ok: false, counter: 5, remainder: 0, ttl: 990 }

    await client.quit();
}

main().catch((err) => {
    console.error(err);
    process.exit(1);
});

npm run file examples/limiter.ts

Benchmarks

npm run file benchmarks/benchmark.ts

Usage no npm install needed!

README

js-counter