node-redis/examples/cuckoo-filter.js

// This example demonstrates the use of the Cuckoo Filter 
// in the RedisBloom module (https://redisbloom.io/)

import { createClient } from 'redis';

async function cuckooFilter() {
  const client = createClient();

  await client.connect();

  // Delete any pre-existing Cuckoo Filter.
  await client.del('mycuckoo');

  // Reserve a Cuckoo Filter with a capacity of 10000 items.
  // https://oss.redis.com/redisbloom/Cuckoo_Commands/#cfreserve
  try {
    await client.cf.reserve('mycuckoo', 10000);
    console.log('Reserved Cuckoo Filter.');
  } catch (e) {
    console.log('Error, maybe RedisBloom is not installed?:');
    console.log(e);
  }

  // Add items to Cuckoo Filter individually with CF.ADD command.
  https://oss.redis.com/redisbloom/Cuckoo_Commands/#cfadd
  await Promise.all([
    client.cf.add('mycuckoo', 'leibale'),
    client.cf.add('mycuckoo', 'simon'),
    client.cf.add('mycuckoo', 'guy'),
    client.cf.add('mycuckoo', 'suze'),
    client.cf.add('mycuckoo', 'brian'),
    client.cf.add('mycuckoo', 'steve'),
    client.cf.add('mycuckoo', 'kyle'),
    client.cf.add('mycuckoo', 'josefin'),
    client.cf.add('mycuckoo', 'alex'),
    client.cf.add('mycuckoo', 'nava'),
  ]);

  // Add items to the Cuckoo Filter only if they don't exist in it...
  // https://oss.redis.com/redisbloom/Cuckoo_Commands/#cfaddnx
  const nxReply = await Promise.all([
    client.cf.addNX('mycuckoo', 'kaitlyn'), // New
    client.cf.addNX('mycuckoo', 'rachel'),  // New
    client.cf.addNX('mycuckoo', 'brian')  // Previously added
  ]);

  console.log('Added members to Cuckoo Filter.');
  console.log('nxReply:');

  // nxReply looks like this:
  // [ 
  //   true, 
  //   true, 
  //   false 
  // ]
  console.log(nxReply);

  // Check whether a member exists with the CF.EXISTS command.
  const simonExists = await client.bf.exists('mycuckoo', 'simon');
  console.log(`simon ${simonExists ? 'may' : 'does not'} exist in the Cuckoo Filter.`);

  // Get stats for the Cuckoo Filter with the CF.INFO command:
  const info = await client.cf.info('mycuckoo');

  // info looks like this:
  // {
  //   size: 16440,
  //   numberOfBuckets: 8192,
  //   numberOfFilters: 1,
  //   numberOfInsertedItems: 12,
  //   numberOfDeletedItems: 0,
  //   bucketSize: 2,
  //   expansionRate: 1,
  //   maxIteration: 20
  // }
  console.log(info);

  await client.quit();
}

cuckooFilter();