题解 | #数组中重复的数字#

rudece加filter

function duplicate(numbers) {
    // write code here
    return numbers.reduce((total, item) => {
        if (numbers.filter((i) => i === item).length > 1) {
            total = item;
        }
        return total;
    }, -1);
}

forEach加filter

function duplicate(numbers) {
    // write code here
    let result = -1;
    numbers.forEach((item) => {
        if (numbers.filter(i => i === item).length > 1) {
            result = item;
        }
    });
    return result;
}
module.exports = {
    duplicate: duplicate,
};