some code to analyse the difference between the union (|) and intersection (&) operates in typescript

union-vs-intersection.ts

type Product = {
  price: number
  sku: string
  brands: {
    _ref: string
  }
  categories: {
    _ref: string
  }
}

type ProductBrand = {
  name: string
  logo: string
}

type ProductCategory = {
  name: string
}

type ProductWithBrands = Omit<Product, "brands"> & {
  brands: ProductBrand
}

type ProductWithCategories = Omit<Product, "categories"> & {
  categories: ProductCategory
}

let product: Product
let productWithBrands: ProductWithBrands
let productWithCategories: ProductWithCategories
let productWithBrandsAndCategories: ProductWithBrands & ProductWithCategories