TypeScript

• Prefer explicit function signatures and narrow types
• Avoid any and non‑null assertions; use safe refinements
• Keep modules small and cohesive

React & JSX

• Use accessible components and proper semantics
• Avoid index keys and non‑interactive handlers on static elements
• Keep hooks top‑level and dependencies correct

Lint & format

Use Ultracite and Biome:

npx ultracite check
npx ultracite fix