5

5.ts

const longestPalindrome = (s: string) => {
  const length = s.length;
  var result = "";
  if (length === 1) {
    return s;
  }

  var fromTheCenter = (left, right) => {
    while (left >= 0 && right < length && s[left] === s[right]) {
      left--;
      right--;
    }

    return s.slice(left + 1, right);
  };

  for (var i = 0; i < length - 1; i++) {
    var oddPal = fromTheCenter(i, i + 1);
    var evenPal = fromTheCenter(i, i);
    if (oddPal.length > result.length) {
      result = oddPal;
    }
    if (evenPal.length > result.length) {
      result = evenPal;
    }
  }
  return result;
};

console.log(longestPalindrome("nan noon is redder"));