Node.js · Streams · Junior · Concept
Explain backpressure in Node streams.
Short Interview Answer
When a writable cannot keep up, it signals the readable to pause — `write` returns false and 'drain' resumes.
Detailed Explanation
Ignoring backpressure causes unbounded memory growth. Prefer `pipeline`/`pipelinePromise` over manual pipe for error propagation. Interviewers love 'what happens if producer is faster than consumer?'