palindrome checker

palindrome.js

/*
 * @param String
 * Using built-in methods, return true if a given string is a palindrome.
**/

function palindrome(str) {
    const invalid = /[\W]/g;
    const normalized = str.toLowerCase().replace(invalid, '');
    const reversed = normalized.split('').reverse().join('');
    return normalized === reversed;
}

/*
 * @param String
 * Using a for loop, return true if a given string is a palindrome.
**/

function palindromeForLoop(str) {
    let reversed = [];
    const invalid = /[\W]/g;
    const normalized = str.toLowerCase().replace(invalid, '');
    for (let i = 0, j = normalized.length; i < j; i++) {
        reversed.push(normalized[j - i - 1])
    }
    reversed = reversed.join('');
    return normalized === reversed;
}