import { Action } from './actions';
import { AbstractControlState, FormState } from './state';
import { ProjectFn } from './update-function/util';
export declare function formStateReducer<TValue>(state: FormState<TValue> | AbstractControlState<TValue> | undefined, action: Action): FormState<TValue>;
/**
 * This function creates a reducer function that first applies an action to the state
 * and afterwards applies all given update functions one after another to the resulting
 * form state. However, the update functions are only applied if the form state changed
 * as result of applying the action. If you need the update functions to be applied
 * regardless of whether the state changed (e.g. because the update function closes
 * over variables that may change independently of the form state) you can simply apply
 * the update manually (e.g. `updateFunction(formStateReducer(state, action))`).
 *
 * The following (contrived) example uses this function to create a reducer that after
 * each action validates the child control `name` to be required and sets the child
 * control `email`'s value to be `''` if the name is invalid.
 *
 * ```typescript
 * interface FormValue {
 *   name: string;
 *   email: string;
 * }
 *
 * const updateFormState = updateGroup<FormValue>(
 *   {
 *     name: validate(required),
 *   },
 *   {
 *     email: (email, parentGroup) =>
 *       parentGroup.controls.name.isInvalid
 *         ? setValue('', email)
 *         : email,
 *   },
 * );
 *
 * const reducer = createFormStateReducerWithUpdate<FormValue>(updateFormState);
 * ```
 */
export declare function createFormStateReducerWithUpdate<TValue>(updateFnOrUpdateFnArr: ProjectFn<FormState<TValue>> | ProjectFn<FormState<TValue>>[], ...updateFnArr: ProjectFn<FormState<TValue>>[]): (state: FormState<TValue> | undefined, action: Action) => FormState<TValue>;