Explain the concept of piping in Node.js streams.

0-2 years experience

1. 1How would you use Node.js streams to read a large CSV file and write only the rows that match a condition to a new file?
2. 2What happens if you create a readable and a writable stream but never call .pipe() between them?

2-5 years experience

1. 1We have a service that downloads a video, transforms it, and uploads it to S3 using streams. It started failing with 'ERR_STREAM_WRITE_AFTER_END'. Walk me through how you'd debug the piping chain.
2. 2Why might you choose to pipe a Transform stream between a Readable and Writable instead of manually handling 'data' events, especially regarding backpressure?

5-8 years experience

1. 1Design a Node.js pipeline that processes incoming HTTP request bodies, validates JSON, compresses the data, and stores it in a database, ensuring the system can handle high concurrency without memory bloat.
2. 2What are the trade‑offs of using .pipe() versus async iterators (for await … of) for a multi‑stage processing pipeline in a microservice handling gigabytes of data per hour?

8+ years experience

1. 1Our platform is migrating a legacy monolith that uses callback‑based file processing to a streaming architecture across multiple services. How would you structure the end‑to‑end data flow, and what considerations around error propagation and backpressure would influence your design?
2. 2When multiple teams need to share a common streaming utility library, what guidelines would you set to keep the pipe‑based APIs stable and performant over time?