import { IReactionOptions } from 'mobx';
declare type ReactionWithOldValueOption = {
    ignoreFirst: boolean;
} & IReactionOptions;
export declare const reactionWithOldValue: <T>(expression: () => T, effect: (newValue: T, oldValue?: T | undefined) => void, opts?: ReactionWithOldValueOption | undefined) => import("mobx").IReactionDisposer;
export {};