{
        vasya: {
            win: 2,
            loss: 2
        },
        petya: {
            win: 1,
            loss: 4
        },
        kolya: {
            win: 3,
            loss: 1
        }
}

var res = {}
win.forEach((k, v)=>{ res[k] = res[k] || { win: 0, loss: 0 }; res[k].win += v; })
loss.forEach((k, v)=>{ res[k] = res[k] || { win: 0, loss: 0 }; res[k].loss += v; })