LeetCode 389. Find the Difference

Input:
s = "abcd"
t = "abcde"

Output:
e

Explanation:
‘e‘ is the letter that was added.

/**
 * @param {string} s 
 * @param {string} t
 * @return {character}
 */
var findTheDifference = function(s, t) {
    let res = 0;
    for(let i = 0 ; i < s.length; i++) {
        res ^= s.charCodeAt(i);
    }
    for(let j = 0 ; j < t.length; j++) {
        res ^= t.charCodeAt(j);
    }
    return String.fromCharCode(res);
    
};
console.log(findTheDifference(‘abcd‘, ‘abcde‘));