JavaScript 程序检查字符串是否可以通过旋转另一个字符串 2 位得到

// function to rotate the string in the left direction
function left_rotate(str){

   // splitting the string and then again joining back
   str = str.substr(2) + str.substr(0,2);
   return str;
}

// function to rotate the string in the right direction
function right_rotate(str){
   // getting the length of the string
   var len = str.length
   // splitting the string and then again joining back
   str = str.substr(len-2) + str.substr(0,len-2)
   return str;
}

// function to check if one string is equal to another after two rotations
function check(str1, str2){

   // checking the size of both strings
   if(str1.length != str2.length){
      return false;
   }
   
   // getting the left rotation of given string
   var l_str = left_rotate(str1);
   
   // getting the right rotation of given string
   var r_str = right_rotate(str1);
   if(r_str == str2 || l_str == str2){
      return true;
   } else {
      return false;
   }
}

// defining the strings
var str1 = "TutorialsPoint"
var str2 = "torialsPointTu"
console.log("The given strings are " + str1 + " and " + str2);

// calling the function
if(check(str1,str2)){
   console.log("Yes, we can obtain the second string from the given string after two rotations");
}
else{
   console.log("No, we cannot obtain the second string from the given string after two rotations");
}