// @flow
import typeof { FirebaseError } from 'firebase';
import type { DataSnapshot, Query } from 'firebase/database';

type LoadingHook<T> = [T | void, boolean, FirebaseError | void];

export type ListHook = LoadingHook<DataSnapshot[]>;
export type ListKeysHook = LoadingHook<string[]>;
export type ListValsHook<T> = LoadingHook<T[]>;
export type ObjectHook = LoadingHook<DataSnapshot>;
export type ObjectValHook<T> = LoadingHook<T>;

declare export function useList(query?: Query | null): ListHook;
declare export function useListKeys(query?: Query | null): ListKeysHook;
declare export function useListVals<T>(
  query?: Query | null,
  options?: {
    keyField?: string,
  }
): ListValsHook<T>;
declare export function useObject(query?: Query | null): ObjectHook;
declare export function useObjectVal<T>(
  query?: Query | null,
  options?: {
    keyField?: string,
  }
): ObjectValHook<T>;