/**
 * 工具
 */
export declare const isObject: (arg: any) => boolean;
export declare const isArray: (arg: any) => boolean;
export declare const isDate: (arg: any) => arg is Date;
export declare const getType: (arg: any) => string;
export declare function extend<T, U>(to: T, from: U): T & U;
export declare function isFormData(val: any): val is FormData;
export declare function isUrlSearchParams(val: any): val is URLSearchParams;
export declare function isAbUrl(url: string): boolean;
export declare function combineUrl(baseUrl: string, url?: string): string;