判断回文数

//回文数判断
let num = 121;
let num2 = 1221;
let num3 = -121;
//判断回文数
fn = (num) => {
  let arr = String(num).split("");
  let newArr = arr.reverse();
  //   console.log(arr);
  let newNum = Number(newArr.join(""));
  //   console.log(newNum);
  if (num === newNum) {
    return console.log("true");
  } else {
    console.log("false");
  }
};
fn(num);//true
fn(num2);//true
fn(num3);//false

//调整
const f= num => {

let newNum = Number(String(num).split("").reverse().join(""));

return num === newNum ? console.log("true"):console.log("false");

}


f(num);//true
f(num2);//true
f(num3);//false