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Sometimes, you may want to enqueue a job in reaction to a frequently occurring event, without running that job for every event. For example, you may want to send an email to a user when they update their profile, but you don’t want to send an email for every single update if they make many changes in rapid succession.

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Using Job IDs for Throttling

You can achieve this by setting an identical jobId so that identical jobs are considered duplicates and not added to the queue. When you use this option, it is up to you to ensure the jobId is unique for different types of work: 
import { Job, Queue, Worker } from 'bullmq';

const myQueue = new Queue('Paint');

const worker = new Worker('Paint', async (job: Job) => {
  console.log('Do something with job');
  return 'some value';
});

worker.on('completed', (job: Job, returnvalue: any) => {
  console.log('worker done painting', new Date());
});

worker.on('failed', (job: Job, error: Error) => {
  console.error('worker fail painting', job, error, new Date());
});

// Add only one job that will be delayed at least 1 second.
myQueue.add('house', { color: 'white' }, { delay: 1000, jobId: 'house' });
myQueue.add('house', { color: 'white' }, { delay: 1000, jobId: 'house' });
myQueue.add('house', { color: 'white' }, { delay: 1000, jobId: 'house' });
myQueue.add('house', { color: 'white' }, { delay: 1000, jobId: 'house' });
myQueue.add('house', { color: 'white' }, { delay: 1000, jobId: 'house' });
myQueue.add('house', { color: 'white' }, { delay: 1000, jobId: 'house' });
myQueue.add('house', { color: 'white' }, { delay: 1000, jobId: 'house' });
In this example, only the first job will be added to the queue. All subsequent attempts to add a job with the same jobId will be ignored while a job with that ID exists in the queue.
Be careful if using removeOnComplete/removeOnFailed options, since a removed job will not count as existing and a new job with the same job ID could be added to the queue without being detected as a duplicate.

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Use Cases

Profile Updates

Send a single notification email after profile updates, not for each field change

Search Indexing

Index a document once after multiple rapid edits

Cache Invalidation

Clear cache once for multiple related changes

Webhook Delivery

Send a single webhook for batched events

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Alternative: Deduplication

For more sophisticated throttling and deduplication patterns, see the Deduplication guide which provides built-in throttle and debounce modes.

Job IDs

Learn more about custom job identifiers

Deduplication

Advanced deduplication strategies

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