export declare function isObject(val: any): val is Object;
export declare function isArrayLike(val: any): val is Object;
export declare function isFunction(val: any): val is Function;
export declare function isString(val: any): val is string;
export declare function isNumber(val: any): val is number;
export declare function assert<E extends Error>(val: boolean, errorConstructor: new (msg: string) => E, message: string): void;