longestPalindrome = (s) => {
    const isEmpty = s.length === 0;
    if (isEmpty) return '';

    const [ left, right ] = search(s);/* Time O(N * N) */

    return s.slice(left, (right + 1));/* Time O(N * N) | Ignore Auxillary Space (N) */
}
Expand Around Center
Time O(N^2) | Space O(1)
https://leetcode.com/problems/longest-palindromic-substring/
@param {string} s
@return {string}