TypeScript Best Practices (TypeScript 5.x)

Type Design

Interface for objects, Type for everything else

// interface: extendable object shapes
interface Animal { name: string; }
interface Dog extends Animal { breed: string; }

// type: unions, intersections, computed types
type Result = Success | Failure;
type Getters<T> = { [K in keyof T as `get${Capitalize<string & K>}`]: () => T[K] };

Discriminated Unions over Optional Properties