شرح الكود

  const categries = [
   "beauty",
  "fragrances",
  "furniture",
  "groceries",
  "home-decoration",
  "kitchen-accessories",
  "laptops",
  "mens-shirts",
  "mens-shoes",
  "mens-watches",
  "mobile-accessories",
  "motorcycle",
  "skin-care",
  "smartphones",
  "sports-accessories",
  "sunglasses",
  "tablets",
  "tops",
  "vehicle",
  "womens-bags",
  "womens-dresses",
  "womens-jewellery",
  "womens-shoes",
  "womens-watches"
  ]

  const [products , setProducts] = useState({});
  useEffect(() => {
    const fetchProductApi = async () => {
        try{
            const result = await Promise.all(
              categries.map(async (category) => {
                const res = await fetch(`https://dummyjson.com/products/category/${category}`)
                const data = await res.json()
                return {[category] : data.products}
              })
            )

            const productsData = Object.assign({},...result)
            setProducts(productsData)
        }catch(e){
          console.error('Fail APi :' , e)
        }
    }
    fetchProductApi()
    console.log(products)
  },[])

اريد شرح لهذا الكود بالتفصيل الممل وماهي دالة all و assign