With Angular HTTP client - How to send POST http object with all attribut `null by default`

Question

My angular component:

const p: Product = this.products.find((d) => d === event.item.data);
p.name = 'foo';

My angular service is:

updateProduct(product: Product): Observable<CommonResult> {
    return this.http.put<CommonResult>(this.configService.getApiUri() + '/products/' + product.productId, product);
}

My Product model:

export class Product {
    id: number;
    name: string;
    category: string = null;
}

I want:

{
  id: 1
  name: "foo",
  category: null
}

but I have:

{
  id: 1
  name: "foo"
}

I do not access to my backend code (I can not change backend code). How to patch my Frontend code to fix my issue?

Answer 1

I patch my update because my GET do not return category: null

{...new Product(), ...product}

full code:

updateProduct(product: Product): Observable<CommonResult> {
    return this.http.put<CommonResult>(this.configService.getApiUri() + '/products/' + product.productId, {...new Product(), ...product});
}