palindrome string in js programiz 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: Function Palindrome JavaScript

function isPalindrome(str) {
  str = str.replace(/\W/g, '').toLowerCase();
  return (str == str.split('').reverse().join(''));
}

console.log(isPalindrome("level"));                   // logs 'true'
console.log(isPalindrome("levels"));                  // logs 'false'
console.log(isPalindrome("A car, a man, a maraca"));  // logs 'true'

Example 3: palindrome js

const palindrome = (str) => {
  var text = str.replace(/[.,'!?\- \"]/g, "")
  return text.search(
    new RegExp(
      text
        .split("")
        .reverse()
        .join(""),
      "i"
    )
  ) !== -1;
}
  
//or
function palindrome(str) {
  let text = str.replace(/[.,'!?\- \"]/g, "").toUpperCase();
  for (let i = 0; i > text.length/2; i++) {
    if (text.charAt(i) !== text.charAt(text.length - 1 - i)) {
      return false;
    }
  }
  return true;
}
console.log(palindrome("Able was I, ere I saw elba.")); //logs 'true'

Example 4: 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;
}