import { Middleware } from "redux";
/** @returns redux middleware to support undo/redo actions.
 *
 * The middleware does two things:
 *
 * 1) for undo/redo actions, the middlware does nothing. The undo/redo reducer will handle those.
 *
 * 2) for normal actions, the middeware dispatches an additional undoSave action to
 * follow the original action. The reducer for the undoSave action will save the state
 * in undo history.
 */
export declare function undoRedo(): Middleware;