/**
 * 分组
 * @param list 列表
 * @param key 关键字
 * @returns
 */
declare function groupBy<T>(list: T[], key: string): Record<string, T[]>;
declare function first<T>(list: T[]): T | undefined;
declare function last<T>(list: T[]): T | undefined;
declare function toList<T>(val: T | T[]): T[];
declare const _default: {
    groupBy: typeof groupBy;
    first: typeof first;
    last: typeof last;
    toList: typeof toList;
};
export default _default;