Function update

update(
    id: number,
    data: {
        category?: Book | Electronics | Misc;
        name?: string;
        price?: number;
        stock?: number;
        user?: number;
    },
): Promise<
    {
        category: ItemCategory;
        id: number;
        name: string;
        price: number;
        stock: number;
        user?: | number
        | { email?: string; id: number; name?: string; username: string };
    },
>
Parameters
- id: number
- data: {
      category?: Book | Electronics | Misc;
      name?: string;
      price?: number;
      stock?: number;
      user?: number;
  }
Returns Promise<
    {
        category: ItemCategory;
        id: number;
        name: string;
        price: number;
        stock: number;
        user?: | number
        | { email?: string; id: number; name?: string; username: string };
    },
>
- Defined in backend/src/services/items.ts:83