Difference between two strings JavaScript

We are given two strings, say s and t. String t is generated by random shuffling string s and then add one more letter at a random position.

We are required to write a JavaScript function that takes both these strings and returns the letter that was added to t.

For example −

If the input stings are −

const s = "abcd", t = "abcde";

Then the output should be −

const output = "e";

because 'e' is the letter that was added.

Example

const s = "abcd", t = "abcde";
const findTheDifference = (s, t) => {
   let a = 0, b = 0; let charCode, i = 0;
   while(s[i]){
      a ^= s.charCodeAt(i).toString(2);
      b ^= t.charCodeAt(i).toString(2);
      i++;
   };
   b^=t.charCodeAt(i).toString(2);
   charCode = parseInt(a^b,2);
   return String.fromCharCode(charCode);
};
console.log(findTheDifference(s, t));

Output

And the output in the console will be −

e