export declare const isUndefined: (value: unknown) => value is undefined;
export declare const isNull: (value: unknown) => value is null;
export declare const isNaN: (number: unknown) => boolean;
export declare const isString: (value: unknown) => value is string;
export declare const isBoolean: (value: unknown) => value is boolean;
export declare const isTrue: (value: unknown) => value is true;
export declare const isFalse: (value: unknown) => value is false;
export declare const isNumber: (value: unknown) => value is number;
export declare const isArray: (arg: any) => arg is any[];
export declare const isError: (value: unknown) => value is Error;
export declare const isFunction: (value: unknown) => value is Function;
export declare const isDate: (value: unknown) => value is Date;
export declare const isObjectNonNull: (value: unknown) => value is object;
export declare const isPureObject: <R extends Record<string, any>>(value: unknown) => value is R;