TypeScript Type Definitions

This Skill provides Claude Code with specific guidance on how it should handle TypeScript types and interfaces.

When to use this skill:

• Defining new types or interfaces in src/lib/types.ts
• Creating request/response payload types for API endpoints
• Defining component prop interfaces
• Adding fields to existing interfaces (RenderRequest, RecapBook)
• Creating enum or const objects for fixed value sets
• Refactoring types for better type safety

Instructions

• Centralized Types: Define all shared types in src/lib/types.ts for consistency
• Interface Naming: Use descriptive names that indicate purpose (RenderRequest, RecapBook, MonthlyRecapExport)
• Strong Typing: Avoid any; use specific types for all function parameters and return values
• Required vs Optional: Use ? for optional fields; avoid excessive optionality
• Type Exports: Export all public-facing types for use across the codebase
• Enum for Constants: Use enums or const objects for fixed sets of values (e.g., AnimationType)
• Readonly Where Appropriate: Use readonly for immutable properties in interfaces

Examples:

// Good: Clear types, required fields explicit, exported
export interface RenderRequest {
  month: number; // 1-12
  year: number;
  books: RecapBook[];
  templateId?: string;
}

export interface RecapBook {
  title: string;
  author: string;
  coverUrl: string;
  rating: number;
  cawpileScores: {
    characters: number;
    atmosphere: number;
    writing: number;
    plot: number;
    intrigue: number;
    logic: number;
    enjoyment: number;
  };
}

// Bad: Vague types, everything optional, not exported
interface Request {
  month?: any;
  year?: any;
  data?: any[];
}