Finding the longest Palindrome in a string and returning the longest single word in Javascript

Question

I writing a method to find the longest palindrome in a sentence of words. So far I have used the for loop to do this but its not returning the correct word.

function findLongestPalindrome(sentence) {
  let wordArray = sentence.split(" ");
  let longestWord = 0;
  let word = " ";
  
  for(let i = 0; i < wordArray.length; i++) {
    if(longestWord < wordArray[i].length) {
      longestWord = wordArray[i].length;
      word = wordArray[i]
    }
  }
  return word;
}

Can anyone give me a tip on where I am going wrong?

Answer 1

You are missing a function to check string is palindrome or not. Please refer the below code and you can further optimize using new Set() and refactoring the code.

function findLongestPalindrome(sentence) {
  let wordArray = sentence.match(/\b\w+\b/g),
      longestWord = 0,
      word = " ";

  for (let i = 0; i < wordArray.length; i++) {
    if (longestWord < wordArray[i].length && isPalindrome(wordArray[i])) {
      longestWord = wordArray[i].length;
      word = wordArray[i]
    }
  }
  
  return word;
}

function isPalindrome(str) {
  return str.split('').reverse().join('') === str;
}

console.log(
  findLongestPalindrome('This is an interesting sentence: kayak, november, anna')
)