mycodedojo · est. 2020
Field notes from the code dojo.
Homelab, self-hosting, AI agents and full-stack craft. I'm Michael Cooper, a senior full-stack engineer who runs most of his stack on hardware in his own house. These are the notes I write while I train.
Featured note
React 19: The New APIs Worth Using Right Now
React 19 shipped the most significant API additions in years. Here is a practical tour of the ones that change how you write components day-to-day.
Fresh off the mat
Latest notes
TIL: findLast() and findLastIndex() — Search Arrays From the End
ES2023 added findLast() and findLastIndex() so you can stop reversing arrays just to find the last matching element.
White belt
Custom React Hooks: Extract, Reuse, and Actually Test Them
Custom hooks are React's best composability tool — here is how to design them well, avoid the common pitfalls, and write tests that give you real confidence.
Green belt
TypeScript Utility Types: The Ones You Will Actually Use
Partial, Pick, Omit, ReturnType, Awaited — six built-in TypeScript helpers that eliminate repetitive type definitions and make refactors painless.
Yellow belt
Core Web Vitals in Next.js: Measuring and Fixing What Actually Matters
LCP, INP, and CLS explained with concrete Next.js fixes — next/image, font optimization, lazy loading, and the useReportWebVitals hook.
Green belt
TIL: toSorted(), toReversed(), toSpliced(), with() — Mutate-Free Array Methods
ES2023 gave JavaScript four non-mutating array methods that return a new array instead of changing the original — a small API improvement with big payoff in React.
Yellow belt
GitHub Actions CI/CD for Your Next.js App
Automate linting, type checking, tests, and Vercel previews on every pull request with a practical GitHub Actions workflow.
Green belt