palindrome.js

const isPalindrome = s => {
    if (s.length < 2) return true;
    if (s[0] !== s[s.length - 1]) return false;
    return isPalindrome(s.substr(1, s.length - 2));
}

const testPalindrome = palindromeMethod => s => {
    const result = palindromeMethod(s) ? "er et palindrom" : "er IKKE et palindrom";
    console.log(s, result);
}

const stringsToTest = ["den laks skal ned", "mellem", "tigerrejer"];
const palindromeTester = testPalindrome(isPalindrome);
stringsToTest.forEach(palindromeTester);