How to rate limit in Deno Serverless scripts using "Rate Limiter Flexible" library

rate-limiter-deno-example.ts

import { serve } from 'https://deno.land/[email protected]/http/server.ts';

import { RateLimiterMemory } from 'https://dev.jspm.io/rate-limiter-flexible';

const rateLimiter = new RateLimiterMemory({
  points: 2, // points available, resets after duration
  duration: 10, // in seconds
});

console.log('Rate Limiter Test');

serve(async (req: any) => {
  console.log('Rate Limiter Request', req);

  let response;

  try {
    const rateLimiterRes = await rateLimiter.consume('userId', 1);
    console.log('Allowed', rateLimiterRes);
    response = new Response(JSON.stringify({ body: 'Allowed' }), { headers: { 'Content-Type': 'application/json' } });
  } catch (err) {
    console.error('Rejected', err);
    response = new Response(JSON.stringify({ status: 429, body: 'Too many ' + err.consumedPoints }), { headers: { 'Content-Type': 'application/json' } });
  }

  return response;
});