leetcode-整数反转

/**
 * @param {number} x
 * @return {number}
 */
var reverse = function(x) {
 let res = 0
 while(x !== 0){
   if((x > Math.pow(2,31) - 1) || x <= Math.pow(-2,31)){
     return 0
   }
    digits = x % 10
    x = parseInt(x / 10)
    //x = ~~(x / 10) ~~代表取整相当于parseINT
    res = res * 10 + digits 

      }
    return res
};

//重点：取模+整数除10+乘10相加