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Vibe codingMediumvc-g540
Subject Ai code reviewLevel Mid–Senior~15 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

You asked an AI agent to format an order total for display. It produced this TypeScript helper and the demo (a US test account) looks perfect. What breaks once this reaches real users, and what's the fix?

ts
export function formatTotal(cents: number, currency: string): string {  const amount = (cents / 100).toFixed(2);  return `$${amount.replace(/\B(?=(\d{3})+(?!\d))/g, ',')}`;}
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.