import { StringCase } from '../types/stringCaseTypes';
/**
 * Internal type used by string preparation utility
 * Not exported as it's an implementation detail
 */
interface StringPreparationResult {
    string: string;
    shouldTransform: boolean;
    sourceCase: StringCase | null;
    singleWord: boolean;
}
/**
 * Prepares a string for case transformation by validating input
 * @param str - The input string to prepare
 * @returns StringPreparationResult object containing the processed parts
 * @throws {Error} If the input is not a string
 * @internal This function is for internal use by the library
 */
export declare function prepareStringTransformation(str: string): StringPreparationResult;
export {};