declare type Options = {
    /** compare the two strings in case insensitive mode */
    caseInsensitive?: boolean;
};
/**
 * Implementation of Longest Common Substring problem.
 * https://en.wikipedia.org/wiki/Longest_common_substring_problem
 *
 * Returns the longest possible substring that is substring of both of given strings.
 *
 * @param array1 First string.
 * @param array2 Second string.
 * @returns A string that is common to both strings such that there is no
 * common substring with size greater than the length of the string.
 */
export declare function longestCommonSubstring(string1: string, string2: string, { caseInsensitive }?: Options): string;
export default longestCommonSubstring;