import { MessageFunctionType, Result } from '../types';
export interface IsAlphaErrors {
    TARGET_ARGUMENT_NOT_A_STRING: MessageFunctionType;
    LOCALE_ARGUMENT_NOT_A_STRING: MessageFunctionType;
    INVALID_LOCALE: MessageFunctionType;
}
export declare const IS_ALPHA_ERRORS: IsAlphaErrors;
/**
 * Tests whether if the string contains only letters
 * valid for the locale.  For the US his would be (a-zA-Z).
 *
 * ### Example
 * ```
 * expect(isAlpha('hello').value).toBeTruthy()
 * ```
 *
 * @param target The target string
 * @param locale The locale argument, defaults to 'en-US'
 */
export declare function isAlpha(target: string, locale?: string): Result<boolean | undefined>;
/**
 * The alpha locales
 */
export declare const isAlphaLocales: string[];