Creating Mapped Types

Creating Mapped Types
πŸ‘¨β€πŸ’Ό You've recreated TypeScript's utility types from scratch!
πŸ¦‰ Key insights:
  • ? adds optional, -? removes it
  • readonly adds readonly, -readonly removes it
  • T[K] gives you the original type to transform
These patterns are used in advanced libraries like Prisma, tRPC, and Zod.

Please set the playground first

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