import { MessageFunctionType, Result } from '../types';
export interface IsUppercaseErrors {
    TARGET_ARGUMENT_NOT_A_STRING: MessageFunctionType;
}
export declare const IS_UPPERCASE_ERRORS: IsUppercaseErrors;
/**
 * Check if `target` is uppercase
 * ### Example
 * ```
 * expect(isUppercase('ABC').value).toBeTruthy()
 * ```
 * @param target The target
 */
export declare function isUppercase(target: string): Result<boolean | undefined>;