找数组中出现最多的元素和次数

<script>
    function findMost(arr) {
        if (!arr.length) return;
        if (arr.length === 1) return 1;
        let res = {};
        let maxName, maxNum = 0;
        // 遍历数组
        arr.forEach((item) => {
            res[item] ? res[item] += 1 : res[item] = 1;;
        });
        // 遍历 res
        for (let r in res) {
            if (res[r] > maxNum) {
                maxNum = res[r];
                maxName = r;
            }
        }
        return '出现次数最多的元素为:' + maxName + ', 出现次数为:' + maxNum;
    }
    console.log(findMost([1, 5, 5, 8, 6, 1, 8, 6, 7, 5]));
</script>