Second Largest Digit in a String

1796. Second Largest Digit in a String

Given an alphanumeric string s, return the second largest numerical digit that appears in s, or -1 if it does not exist.

An alphanumeric string is a string consisting of lowercase English letters and digits.

### Example 1:
Input: s = "dfa12321afd"
Output: 2
Explanation: The digits that appear in s are [1, 2, 3]. The second largest digit is 2.

### Example 2:
Input: s = "abc1111"
Output: -1
Explanation: The digits that appear in s are [1]. There is no second largest digit. 

Constraints:
1 <= s.length <= 500
s consists of only lowercase English letters and/or digits.

/**
 * @param {string} s
 * @return {number}
 */
var secondHighest = function(s) {
    let firstLarge = -1, secondLarge = -1;
    for (let i = 0; i < s.length; i++) {
       const num = +s[i];
       if (!Number.isInteger(num)) {
           continue;
       }
       
       if (num > firstLarge) {
           secondLarge = firstLarge;
           firstLarge = num;
       } else if (num !== firstLarge && num > secondLarge) {
           secondLarge = num;
       }
    }    
    return secondLarge;
};