import type { ComputedRef, Ref, UnwrapRef } from 'vue';
export declare function useMergedState<T>(defaultStateValue: T | (() => T), option?: {
    defaultValue?: T | (() => T);
    value?: Ref<T> | Ref<UnwrapRef<T>>;
    onChange?: (val: T, prevValue: T) => void;
    postState?: (val: T) => T;
}): [ComputedRef<T>, (val: T) => void];