import { MaybePromise } from './utils';
export type DataState<T> = {
    kind: 'loading';
} | {
    kind: 'loaded';
    data: T;
} | {
    kind: 'error';
    error: Error;
};
export declare const LOADING: unique symbol;
export declare function useData<T>(func: () => MaybePromise<T | typeof LOADING>): DataState<T>;
export declare function mergeDataStates<T extends Record<string, unknown>>(input: {
    [K in keyof T]: DataState<T[K]>;
}): DataState<T>;