TypeScript Mapped Types

Mapped types transform existing types into new ones. Here's how to use them effectively.

Best Practices#

Design:
✓ Use meaningful type names
✓ Document complex transformations
✓ Keep transformations simple
✓ Compose small mapped types

Performance:
✓ Avoid deep recursion
✓ Use constraints to limit keys
✓ Test with real types
✓ Check compilation time

Patterns:
✓ Key remapping for naming conventions
✓ Conditional mapping for type variations
✓ Modifiers for optional/readonly
✓ Filtering for type subsets

Mapped types transform types by iterating over keys. Use them for creating variations like readonly or optional versions, generating getter/setter types, and transforming nested structures. Key remapping enables powerful naming transformations.

TypeScript Mapped Types

Basic Mapped Types#

Key Filtering#

Key Remapping#

Conditional Mapping#

Union to Object#

Property Modifiers#

Index Signatures#

Practical Examples#

Recursive Mapped Types#

Combining Mapped Types#

Best Practices#

Conclusion#

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