typescript.md

TypeScript Rules

Apply these rules when migrating files from JavaScript to TypeScript

General Guidelines

• Do not introduce unrelated logic changes while adding types
• Favor type safety over convenience (any is a last resort)
• Use existing project patterns and types when available
• Prefer inference when it is clear and sufficient

Typing Strategy

• Use existing types/interfaces from the codebase
• Define minimal types/interfaces when needed
• Use unknown over any when type is unclear
• Use any only as a temporary fallback
• Organize types in dedicated files (types.ts) or alongside implementations
• Create a central types.ts file or a src/types directory for shared types

React & Redux

• Type props explicitly using type or interface
• Use typed hooks (useAppDispatch, useAppSelector) instead of raw Redux hooks
• Type event handlers (React.ChangeEvent, etc.)

State & Data

• Avoid initializing empty arrays/objects without types (useState<Type[]>([]))
• Prevent never[] by explicitly typing initial state
• Use union types for nullable/optional values (string | null)

API

• Type all API requests and responses
• If API request/response types are unclear, ask for the API spec instead of guessing