const firstNonRepeatingCharacter = (str) => {
    for (let i = 0; i < str.length; i++) {
        let seenDuplicate = false;
      console.log("pass");
        for (let j = 0; j < str.length; j++) {
            if (str[i] === str[j] && i !== j) {
                seenDuplicate = true;
                break;
            }
        }
        if (!seenDuplicate) {
            return str[i];
        }
    }
    return null; // return null if no unique character is found
};