Hi I am struggling getting Typescript to work with my current setup. For reference this is cut down version of my prisma Model.

model Invoice {
  id              String    @id @default(uuid())
  invoiceNumber   String?

  clientId String?
  client   Client? @relation(fields: [clientId], references: [id])

  companySettings CompanySettings @relation(fields: [companyId], references: [id])
  companyId       String

  lineItems InvoiceLineItem[]

  userId String
  user   User   @relation(fields: [userId], references: [id])
}

model InvoiceLineItem {
  id              String  @id @default(uuid())
  itemName        String?
  invoice         Invoice @relation(fields: [invoiceId], references: [id])
  invoiceId       String
}

model Client {
  id           String    @id @default(uuid())
  name         String    @unique @db.VarChar(256)
  user         User      @relation(fields: [userId], references: [id])
  userId       String    @db.VarChar(256)
  invoices     Invoice[]
}

So a Client can have many invoices. An Invoice can have many lineItems. So I tried replicating this as an interface

export interface InvoiceLineItem {
  id: string;
  itemName?: string | null;
  invoiceId: string;
}

export interface Invoice {
  id: string;
  invoiceNumber?: string | null;
  clientId?: string | null;
  companyId: string;
  lineItems?: InvoiceLineItem[];
  userId: string;
}

export interface Client {
  id?: string;
  name: string;
  userId: string;
  invoices?: Invoice[];
}

So I want to retrieve all clients so I have the following

export const fetchClients = async (): Promise<Client[] | null> => {
  try {
    const clientsRes = await GetClients();
    if (clientsRes.success && clientsRes.clients) {
      return clientsRes.clients;
    } else {
      return null;
    }
  } catch (error) {
    console.error(error);
    return null;
  }
};

Whats returned is something like this

[
  {
    id: '70414b0a-a9f2-400f-8c88-e57cb9ca2050',
    name: 'Test client',
    creationDate: 2024-06-03T14:40:00.181Z,
    userId: 'asdasd',
    invoices: []
  }
]

Now at this point its one client, with no invoices, hence no lineItems. But I would have thought an empty lineItems array would be included in the response as my action is this

 const clients = await db.client.findMany({
      where: {
        userId: user.id ? { equals: user.id } : undefined,
      },
      include: {
        invoices: {
          include: {
            lineItems: true,
          },
        },
      },
    });

And I think thats where fetchClients is complaining, more specifically return clientsRes.clients; I get

Type '({ invoices: ({ lineItems: { id: string; itemName: string | null; invoiceId: string; }[]; } & { ...; })[]; } & { ...; })[]' is not assignable to type 'Client[]'.
    Types of property 'invoices' are incompatible.
      Type '({ lineItems: { id: string; itemName: string | null; invoiceId: string; }[]; } & { ...; })[]' is not assignable to type 'Invoice[]'.

Am I missing something here? Is it complaining due to not having lineItems in the response? Sorry, first time using Typescript to trying to fully understand things.

Thanks