Security and Performance Guardrails

After a successful refactor in the last lesson, your daily budget tracker app is in great shape. You’ve modularized your components, optimized rendering, and cleaned up your logic using a custom debounce hook. The app looks sleek, responds fast, and runs smoothly.

You’re confident. Your tests pass. You push the final commit to the main branch and notify the team that the app is production-ready.

Just a few minutes later, your CTO drops this message in Slack:

CTO Message:
“Before we ship, let’s tighten security and confirm the performance gains. Use Copilot to scan for risky code and suggest fixes. I want both speed and safety in production. This App.js is copy-pasted spaghetti. Split concerns, performance budget of < 50 ms for search filtering, and drop a quick design diagram before I review the merge.”

Now, your job isn’t related to making the app work. It’s also related to hardening it for real-world use. This is where security and performance guardrails come in, and GitHub Copilot is about to become your best tool for the job.

Let’s get started!

Clone the repository in your VS Code:

Test your commands in the terminal:

With your refactored daily budget tracker ready, the next step before production is ensuring that it’s secure, especially where user input is involved. Rather than setting up external security tools, ...