message: FunctionStack: Fix issue when stack returns undefined
diff: @@ -41,12 +41,12 @@ function getExports(app: App) {
  export function use<T>(stack: FunctionalStack<T>): T {
  if (!currentApp) throw new Error("No app is set");
  - const exists = getExports(currentApp).get(stack);
  - if (!exists)
  + const exports = getExports(currentApp);
  + if (!exports.has(stack))
  throw new Error(
  `StackWrongOrder: Initialize "${stack.name}" stack before "${currentStack?.name}" stack`
  );
  - return exists;
  + return exports.get(stack);
  }
  export type StackContext = {
  