Function onSnapshot

onSnapshot<
    AppModelType = DocumentData,
    DbModelType extends DocumentData = DocumentData,
>(
    reference: DocumentReference<AppModelType, DbModelType>,
    observer: {
        complete?: () => void;
        error?: (error: Error) => void;
        next?: (snapshot: DocumentSnapshot<AppModelType, DbModelType>) => void;
    },
): Unsubscribe

onSnapshot<
    AppModelType = DocumentData,
    DbModelType extends DocumentData = DocumentData,
>(
    reference: DocumentReference<AppModelType, DbModelType>,
    options: SnapshotListenOptions,
    observer: {
        complete?: () => void;
        error?: (error: Error) => void;
        next?: (snapshot: DocumentSnapshot<AppModelType, DbModelType>) => void;
    },
): Unsubscribe

onSnapshot<
    AppModelType = DocumentData,
    DbModelType extends DocumentData = DocumentData,
>(
    reference: DocumentReference<AppModelType, DbModelType>,
    onNext: (snapshot: DocumentSnapshot<AppModelType, DbModelType>) => void,
    onError?: (error: Error) => void,
    onCompletion?: () => void,
): Unsubscribe

onSnapshot<
    AppModelType = DocumentData,
    DbModelType extends DocumentData = DocumentData,
>(
    reference: DocumentReference<AppModelType, DbModelType>,
    options: SnapshotListenOptions,
    onNext: (snapshot: DocumentSnapshot<AppModelType, DbModelType>) => void,
    onError?: (error: Error) => void,
    onCompletion?: () => void,
): Unsubscribe

onSnapshot<
    AppModelType = DocumentData,
    DbModelType extends DocumentData = DocumentData,
>(
    query: Query<AppModelType, DbModelType>,
    observer: {
        complete?: () => void;
        error?: (error: Error) => void;
        next?: (snapshot: QuerySnapshot<AppModelType, DbModelType>) => void;
    },
): Unsubscribe

onSnapshot<
    AppModelType = DocumentData,
    DbModelType extends DocumentData = DocumentData,
>(
    query: Query<AppModelType, DbModelType>,
    options: SnapshotListenOptions,
    observer: {
        complete?: () => void;
        error?: (error: Error) => void;
        next?: (snapshot: QuerySnapshot<AppModelType, DbModelType>) => void;
    },
): Unsubscribe

onSnapshot<
    AppModelType = DocumentData,
    DbModelType extends DocumentData = DocumentData,
>(
    query: Query<AppModelType, DbModelType>,
    onNext: (snapshot: QuerySnapshot<AppModelType, DbModelType>) => void,
    onError?: (error: Error) => void,
    onCompletion?: () => void,
): Unsubscribe

onSnapshot<
    AppModelType = DocumentData,
    DbModelType extends DocumentData = DocumentData,
>(
    query: Query<AppModelType, DbModelType>,
    options: SnapshotListenOptions,
    onNext: (snapshot: QuerySnapshot<AppModelType, DbModelType>) => void,
    onError?: (error: Error) => void,
    onCompletion?: () => void,
): Unsubscribe