how to check given string is palindrome or not in js code example

Example 1: palindrome in javascript

function palindrome(str) {

    var len = str.length;
    var mid = Math.floor(len/2);

    for ( var i = 0; i < mid; i++ ) {
        if (str[i] !== str[len - 1 - i]) {
            return false;
        }
    }

    return true;
}

Example 2: javascript palindrome

function remove_spaces_strict(string)
{
    return string.replace(/\s/gm, "");
}

function to_lower_case(string="")
{
    return string.toLocaleLowerCase();
}


function isPalindrome(string) {
    let string1 = string;
    if (typeof string === 'string' || typeof string === 'number') {
        if (typeof string === 'number') {
            string1 = new Number(string1).toString();
        }
        string1 = remove_spaces_strict(string1);
        string1 = to_lower_case(string1);
        let len1 = string1.length;
        let len = Math.floor(string1.length / 2);
        let i = 0;

        while(i < len) {
    
                if (string1[i] !== string1[len1 - (1 + i)]) {
                    return false;
                }
                console.log(string1[i] + " = " + string1[len1 - (1 + i)]);
                i++;
            }
    }else{
        throw TypeError(`Was expecting an argument of type string1 or number, recieved an argument of type ${ typeof string1}`);
    }
    return string;
}