export declare const isUndefined: (x: any) => boolean;
export declare const isType: (type: string) => (x: any) => boolean;
export declare const isArray: (x: any) => boolean;
export declare const isString: (x: any) => boolean;
export declare const isFunction: (x: any) => boolean;
export declare const isNull: (x: any) => boolean;
export declare const isPlainObject: (x: any) => boolean;
export declare const isNumber: (x: any) => x is number;
export declare const isBoolean: (x: any) => x is boolean;