TypeScript / JavaScript Coding Standards

Scope: TypeScript, JavaScript, React, and Node.js specific patterns with code examples. Universal principles (immutability, error handling, file organization, quality checklist) are defined in rules/common/coding-style.md — always active, not repeated here. For TypeScript type system patterns, see: typescript-patterns and typescript-patterns-advanced

Concrete coding standards and patterns for TypeScript, JavaScript, React, and Node.js projects. Not applicable to Go, Python, Java, or other languages — use language-specific skills instead.

When to Activate

• Starting a new TypeScript, JavaScript, React, or Node.js project or module
• Reviewing TS/JS code for quality and maintainability
• Refactoring TypeScript/React code to follow conventions
• Enforcing naming, formatting, or structural consistency in a TS/JS codebase
• Setting up ESLint, Prettier, or TypeScript compiler rules
• Onboarding new contributors to a TypeScript/JavaScript project

Code Quality Principles