/**
 * Converts the first character of `string` to lower case.
 *
 * @since 5.7.0
 * @category String
 * @param str The string to convert.
 * @returns Returns the converted string.
 * @example
 *
 * ```js
 * lowerFirst('Fred')
 * // => 'fred'
 *
 * lowerFirst('FRED')
 * // => 'fRED'
 * ```
 */
export declare function lowerFirst(str?: string): string;
export default lowerFirst;