First Unique Character in a String

def firstUniqChar(s):
    from collections import Counter

    char_count = Counter(s)

    for i, char in enumerate(s):
        if char_count[char] == 1:
            return i

    return -1

class Solution {
public:
    int firstUniqChar(string s) {
        unordered_map<char, int> count;

        for (char c : s) {
            count[c]++;
        }

        for (int i = 0; i < s.length(); i++) {
            if (count[s[i]] == 1) {
                return i;
            }
        }

        return -1;
    }
};

function firstUniqChar(s: string): number {
    const count = new Map<string, number>();

    for (const char of s) {
        count.set(char, (count.get(char) || 0) + 1);
    }

    for (let i = 0; i < s.length; i++) {
        if (count.get(s[i]) === 1) {
            return i;
        }
    }

    return -1;
}