LeetCode——第一个只出现一次的字符｜刷题打卡

var firstUniqChar = function (s) {
    const m = new Map();
    const flag = 1;
    for (let v of s) {
        if (m.has(v) === false) {
            m.set(v,flag)
        } else {
            m.set(v,m.get(v)+1);
        }
    }
    var result = ' ';
    for (let v of m) {
        if (v[1] === 1) {
            result = v[0];
            break;
        }
    }
    return result;
};