bloom-filter.js

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

import { createClient } from 'redis';

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

  await client.connect();

  // Delete any pre-existing Bloom Filter.
  await client.del('mybloom');

  // Reserve a Bloom Filter with configurable error rate and capacity.
  // https://oss.redis.com/redisbloom/Bloom_Commands/#bfreserve
  try {
    await client.bf.reserve('mybloom', 0.01, 1000);
    console.log('Reserved Bloom Filter.');
  } catch (e) {
    if (e.message.endsWith('item exists')) {
      console.log('Bloom Filter already reserved.');
    } else {
      console.log('Error, maybe RedisBloom is not installed?:');
      console.log(e);
    }
  }

  // Add items to Bloom Filter individually with BF.ADD command.
  await Promise.all([
    client.bf.add('mybloom', 'leibale'),
    client.bf.add('mybloom', 'simon'),
    client.bf.add('mybloom', 'guy'),
    client.bf.add('mybloom', 'suze'),
    client.bf.add('mybloom', 'brian'),
    client.bf.add('mybloom', 'steve'),
    client.bf.add('mybloom', 'kyle'),
    client.bf.add('mybloom', 'josefin'),
    client.bf.add('mybloom', 'alex'),
    client.bf.add('mybloom', 'nava'),
  ]);

  // Add multiple items to Bloom Filter at once with BF.MADD command.
  await client.bf.mAdd('mybloom', [
    'kaitlyn', 
    'rachel'
  ]);

  console.log('Added members to Bloom Filter.');

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

  // Check whether multiple members exist with the BF.MEXISTS command:
  const [ lanceExists, leibaleExists ] = await client.bf.mExists('mybloom', [
    'lance',
    'leibale'
  ]);

  console.log(`lance ${lanceExists ? 'may' : 'does not'} exist in the Bloom Filter.`);
  console.log(`leibale ${leibaleExists ? 'may' : 'does not'} exist in the Bloom Filter.`);

  // Get stats for the Bloom Filter with the BF.INFO command:
  const info = await client.bf.info('mybloom');
  // info looks like this:
  //
  //  {
  //    capacity: 1000,
  //    size: 1531,
  //    numberOfFilters: 1,
  //    numberOfInsertedItems: 12,
  //    expansionRate: 2
  //  }
  console.log(info);

  await client.quit();
}

bloomFilter();