Code Room
Vibe codingMediumvc-g205
Subject Ai prompt specLevel Mid–Senior~14 minCommon in Algorithms & data structures interviewsIndustries Software development, Technology

Question

You're asking an AI agent to write a JavaScript function that decides whether a user's wallet balance is 'enough' to cover a purchase and computes the remaining balance, for an e-commerce checkout. Write the spec that makes the comparison and subtraction monetarily correct in JS specifically. What numeric representation and comparison rules do you mandate, and what acceptance criteria prove it? Then describe what a naive prompt ('check if balance >= price and subtract') produces that lets the wrong transactions through.

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.

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.