The regular expression given in the solution is wrong. It should be "/^[A-Za-z0-9]/g"

class Solution {
// tow pointer solution
  isPalindrome(s) {
    let left = 0, right = s.length -1;

    while(left < right){

        while(left < right && !s[left].match(/^[A-Za-z0-9]/g )) {
            left++
        }
        while(left < right && !s[right].match(/^[A-Za-z0-9]/g )) {
            right--
        }
        if(s[left].toLowerCase() != s[right].toLowerCase())
            return false
            left++
            right--
    }
    // two pointers cross over
    return true
  }
}