What is the pause() method used for in a readable stream, and how can you resume data flow?

0-2 years experience

1. 1You need to read a large file line by line using a readable stream, but the process runs out of memory. How would you use pause() and resume() to fix it?
2. 2If you call stream.pause() and never call stream.resume(), what will happen to the 'data' events?

2-5 years experience

1. 1While building a real‑time log aggregation service, the upstream source sends data faster than your processor can handle, causing backpressure. Walk me through how you'd use pause() and resume() to manage the flow and what pitfalls to watch for.
2. 2During debugging you see a readable stream still emitting 'data' events after you called pause(). What could cause that, and how would you verify the stream’s state?

5-8 years experience

1. 1Design a Node.js microservice that consumes a high‑throughput Kafka topic via a readable stream and forwards messages to a downstream HTTP API. Explain how you'd coordinate pause() and resume() across multiple async workers to avoid overwhelming the API while keeping latency low.
2. 2At scale you need to implement graceful shutdown of a streaming pipeline that uses pause() to stop intake. Describe the steps and edge cases you’d handle to ensure no data loss or duplication.

8+ years experience

1. 1Our platform is migrating legacy EventEmitter‑based streams to the async iterator pattern. As the lead architect, how would you evaluate whether to keep using pause()/resume() or replace them, considering cross‑team maintenance, backpressure semantics, and observability?
2. 2Several services share a common streaming library that uses pause() for rate limiting. If we need dynamic throttling based on runtime metrics, what architectural changes would you propose, and how would you expose control without breaking existing contracts?