Advanced TypeScript Patterns for Better APIs

TypeScript's type system is incredibly powerful when used effectively. Here are advanced patterns I use to build better APIs.

Conditional Types

Create types that adapt based on their input type parameters.

Template Literal Types

Build compile-time validated API endpoint types.

Branded Types

Create distinct types for IDs to prevent accidental misuse.

Result Types for Error Handling

Type-safe error handling with discriminated unions.

Builder Pattern with Fluent Interface

Create query builders with full type safety.

Mapped Types for API Validation

Use RequireFields and PartialExcept for request validation.

These patterns help create APIs that are not just functional, but truly type-safe and maintainable at scale.