longest-palindrome.js

function is_Palindrome(str1) {
    return str1 == str1.split('').reverse().join('')
}

function longest_palindrome(str1) {
    let max_length = 0, maxp = ''
    for (var i = 0; i < str1.length; i++) {
        var subs = str1.substr(i, str1.length)
        for (var j = subs.length; j >= 0; j--) {
            var sub_subs_str = subs.substr(0, j)
            if (sub_subs_str.length <= 1)
                continue
            if (is_Palindrome(sub_subs_str)) {
                if (sub_subs_str.length > max_length) {
                    max_length = sub_subs_str.length
                    maxp = sub_subs_str
                }
            }
        }
    }

    return maxp;
}
console.log(longest_palindrome("abracadabra"))
console.log(longest_palindrome("HYTBCABADEFGHABCDEDCBAGHTFYW12345678987654321ZWETYGDE"))