Mastering TypeScript Generics for Library Authors

Why Generics Matter

Generics allow your components to accept data of various shapes while still guaranteeing type safety. It's the difference between any and precise, autocompleted code.

Inferred Types

The real power comes when you let TS infer the type from the argument.

function createHandler<T>(data: T): { payload: T } { ... }

Conditional Types

Using T extends U ? X : Y allows you to create types that change based on inputs. This is crucial for things like polymorphic components (e.g. a Button that acts like an <a> tag if an href is passed).