最长回文子串

给定一个字符串 s，找到 s 中最长的回文子串 //babad—>bab

const centerLogic=(str,left,right){
  while(left>=0&&right<str.length-1;i++){
    left--;
    right++;
  }
  return str.slice(letf+1,right)
}
const longestPrefitStr=(s)=>{
  let result='';
  for(let i=0;i<s.length;i++){
    const odd=centerLogic(s,i,i);
    const even=centerLogic(s,i,i+1);
    if(odd.length>result.lenth) result=odd;
    if(even.length>result.lenth) result=even;
  }
  return result;
}