Deduplication interview questions
Practice 3 questions on deduplication. Each runs in a real in-browser editor with Jest tests and a worked, diagram-backed solution.
3 questions
- EASY
Array XOR (Symmetric Difference)
Implement lodash xor — return the values that appear in exactly one of the given arrays, with duplicates removed.
20 minJavaScript - MEDIUM
Idempotency Key Queue
Dedupe by idempotency key: run a task at most once per key, cache the result with a TTL, and retry on failure.
35 minJavaScript - MEDIUM
WebSocket Session Resume
PREMIUMResume a dropped connection without gaps — track sequence numbers, request a replay from the last seen, and de-duplicate redelivered messages.
40 minJavaScript