How to sum a array like a Excel Pivot where two keys must match?

const
    data = [{ Datum: { date: "2000-01-01 00:00:00.000000", timezone_type: 3, timezone: "Europe/Berlin" }, Material: "123", Menge: 100, Fehler: 5 }, { Datum: { date: "2000-01-01 00:00:00.000000", timezone_type: 3, timezone: "Europe/Berlin" }, Material: "123", Menge: 5, Fehler: 1 }, { Datum: { date: "2000-01-01 00:00:00.000000", timezone_type: 3, timezone: "Europe/Berlin" }, Material: "123", Menge: 6, Fehler: 65 }, { Datum: { date: "2000-01-01 00:00:00.000000", timezone_type: 3, timezone: "Europe/Berlin" }, Material: "222", Menge: 10, Fehler: 5 }, { Datum: { date: "2000-01-02 00:00:00.000000", timezone_type: 3, timezone: "Europe/Berlin" }, Material: "444", Menge: 29, Fehler: 1 }, { Datum: { date: "2000-01-02 00:00:00.000000", timezone_type: 3, timezone: "Europe/Berlin" }, Material: "123", Menge: 1, Fehler: 1 }],
    result = Object.values(data.reduce((acc, { Datum: { date }, Material, Menge, Fehler }) => {
        const
            Datum = date.slice(0, 10),
            key = [Datum, Material].join('|');

        acc[key] ??= { Datum, Material, Menge: 0, Fehler: 0 };
        acc[key].Menge += Menge,
        acc[key].Fehler += Fehler;

        return acc;
    }, {}));

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }