Longest palindrome

lp.ts

function longestPalindrome(s: string): string {
    let result = "";
    let resultLength = 0;
    
    for (let i = 0; i < s.length; i++) {
        // odd length palindromes
        let leftPointer = i, rightPointer = i;
        
        while (leftPointer >= 0 && rightPointer < s.length && s[leftPointer] === s[rightPointer]) {
            if ((rightPointer - leftPointer + 1) > resultLength) {
                result = s.slice(leftPointer, rightPointer + 1);
                resultLength = result.length;
            }
            
            leftPointer--;
            rightPointer++;
        }
        
        // even length palindromes
        leftPointer = i;
        rightPointer = i + 1;
        
        while (leftPointer >= 0 && rightPointer < s.length && s[leftPointer] === s[rightPointer]) {
            if ((rightPointer - leftPointer + 1) > resultLength) {
                result = s.slice(leftPointer, rightPointer + 1);
                resultLength = result.length;
            }
            
            leftPointer--;
            rightPointer++;
        }
        
    }
    
    return result;
};

Inspired by https://www.youtube.com/watch?v=XYQecbcd6_c