How to speed up program execution JS [closed]

I have this code:

module.exports = function (N, staff, K) {
    staff.sort((a, b) => b - a);
    let sliced = staff.slice(0, K);

    return sliced.slice(0, K).reduce((a, b)=>{
        return a+b
    }, 0);
}

I would like to hear your suggestions on how to speed up its execution as much as possible