Function updateFormState

packages/core/src/forms/useForm.ts:58–69

(
    nextState: FormState<T> | ((prev: FormState<T>) => FormState<T>),
  )

  const fieldArrayKeyCounterRef = ctx.useRef<number>(0);

  const updateFormState = (
    nextState: FormState<T> | ((prev: FormState<T>) => FormState<T>),
  ): void => {
    setState((prev) => {
      const resolved =
        typeof nextState === "function"
          ? (nextState as (prev: FormState<T>) => FormState<T>)(prev)
          : nextState;
      stateRef.current = resolved;
      return resolved;
    });
  };

  const wizardSteps = options.wizard?.steps ?? [];
  const stepCount = wizardSteps.length;