Function: typedSpec()

API / @xmachines/play-actor / typedSpec

function typedSpec<TContext>(spec): PlaySpec;

Defined in: packages/play-actor/src/abstract-actor.ts:83

Identity helper that constrains a PlaySpec object’s contextProps to keys of a specific machine context type, giving compile-time validation and IDE autocomplete at the definition site.

XState’s meta field is typed as Record<string, unknown>, so TypeScript cannot infer the constraint from context. typedSpec<MyCtx>(...) is the opt-in mechanism that activates enforcement where the spec is written.

At runtime this is a no-op — the spec object is returned unchanged.

Type Parameters

Type Parameter
TContext extends object

Parameters

Parameter	Type
spec	Omit<PlaySpec, "contextProps"> & object

Returns

PlaySpec

Example

interface DashboardCtx {
  username: string;
  params: Record<string, string>;
  query: Record<string, string>;
}

meta: {
  view: typedSpec<DashboardCtx>({
    root: "root",
    contextProps: ["username"],    // ✓ key of DashboardCtx
    // contextProps: ["usernaem"], // ✗ compile error
    elements: { root: { type: "Dashboard", props: {}, children: [] } },
  }),
}