Object types

Goal: Declare object shapes with the type brace form.

SJS uses type Name { ... } for structural types. Conformance is checked structurally — no implements keyword.

Example

type Point {
  x: number;
  y: number;
}

type Named {
  name: string;
}

type Place extends Named {
  city: string;
}

function label(p: Place): string {
  return p.name + " @ " + p.city
}

Open in playground

Key takeaways

• Members end with semicolons.
• extends composes object types.
• Classes satisfy object types implicitly.

Next: Generics