TypeScript Mapped Types

Transform object types systematically using mapped types, modifiers, and key remapping.

Usage

Describe the type transformation you need and get mapped type solutions.

Examples

• "Make all properties of an interface readonly"
• "Create a type that makes specific properties required"
• "Remap keys to add a prefix using mapped types"

Guidelines

• Show the basic [K in keyof T] syntax and modifier operators
• Cover key remapping with the as clause
• Include filtering keys with conditional types in mapped types
• Explain how built-in utility types use mapped types internally
• Show composition of mapped types for complex transformations