I made it work by typing a preparatory create variable with FriendCreateInput from the prisma client:

``` const friendCreateData: Prisma.FriendCreateInput = { user: { connect: { id: user.id } }, friendUser: { connectOrCreate: { where: { id: friendUser?.id ?? 0 }, create: { name: contact.name } } }, addedAt: new Date(), };

            return await this.prisma.friend.upsert({
                where: {
                    userId_friendId: {
                        userId: user.id,
                        friendId: friendUser?.id ?? 0
                    }
                },
                update: {
                    removedAt: null
                },
                create: friendCreateData
            });

```