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Vibe codingHardvc-g513
Subject Ai code reviewLevel Senior–Staff~19 minCommon in Algorithms & data structures interviewsIndustries Software development, Technology

Question

An AI assistant wrote this Lambda (TypeScript) with a lazily-initialized client to avoid paying init cost on cold starts. Occasionally requests fail with 'client is undefined' right after a deploy. Find the bug and explain when it triggers.

ts
let client: ApiClient; async function init() {  client = await ApiClient.connect(process.env.API_URL!);}init(); // kick off init at module load, don't await export const handler = async (event: any) => {  const data = await client.fetch(event.id); // assumes client ready  return { data };};
What a strong answer looks like

Treat the AI’s output as a draft to verify, not an answer to trust. Name the specific flaw and the input that triggers it, say how you’d catch it — tests, edge cases, reading critically — and how you’d re-prompt or decompose to get it right.

Learn the concepts
Describe your solution

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.