examples/bloom-filter.js
// This example demonstrates the use of the Bloom Filter
// in the RedisBloom module (https://redis.io/docs/stack/bloom/)
import { createClient } from 'redis';
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://redis.io/commands/bf.reserve/
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.
// https://redis.io/commands/bf.add/
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.
// https://redis.io/commands/bf.madd/
await client.bf.mAdd('mybloom', [
'kaitlyn',
'rachel'
]);
console.log('Added members to Bloom Filter.');
// Check whether a member exists with the BF.EXISTS command.
// https://redis.io/commands/bf.exists/
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.
// https://redis.io/commands/bf.mexists/
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.
// https://redis.io/commands/bf.info/
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();