TypeScript Coding Standards

Core Rules

• TS strict mode. Zero any. Zero untyped exports.
• Explicit return types on all exported functions.
• Interfaces for object shapes. Type aliases for unions/intersections.
• Async/await over raw promises. Always try/catch with typed errors.
• Optional chaining (?.) and nullish coalescing (??) over manual null checks.
• Never use non-null assertion (!) unless justified with a comment.
• const by default. let only when value changes. Never var.
• Destructuring for cleaner code. Template literals for string interpolation.

File Limits

• Functions: <40 lines. Extract if exceeding.
• Files: <300 lines. Split if exceeding.
• No dead code. No unused imports. No commented-out blocks.