Type System

TypeScript types compile to Luau type annotations — they are preserved, not erased. This is one of the core differences from roblox-ts, whose output is untyped.

interface Props {              // type Props = {
  title: string;               //   title: string,
  count?: number;              //   count: number?,
  items: string[];             //   items: { string },
  data: Record<string, number>; //  data: { [string]: number },
  onClick: () => void;         //   onClick: (() -> ()),
}                              // }

enum Direction { Up, Down }    // local Direction = { Up = 0, Down = 1 }
                               // type Direction = number

Supported type constructs

• Interfaces and type aliases
• Generics
• Union and intersection types
• Optionals (?) and Record<K, V> index signatures
• Utility types: Partial<T>, NonNullable<T>, Readonly<T>, Required<T>
• Conditional types, mapped types, template literal types, indexed access types
• Enums (compiled to a value table plus a number type alias)

See the types example for a full side-by-side input/output pair.

Type extraction for packages

Installed Luau packages don’t ship TypeScript types. The rbx-tsx types command reads your installed wally/pesde package source and emits .d.ts declarations so those imports resolve to real types instead of any.