I have a set of product details stored in firestore. I've created a custom hook to fetch the product details. The product categories should be displayed in the matching URL param. As I add more product categories to be displayed in other URLs, the product cards don't render on mount. When I try to edit the productcard component, the product card renders and disappears in seconds. The data is being fetched correctly and is being rendered properly, but the rendered product card disappears in seconds. I'm unable to figure what the issue is as there's no error in the console. Could it be anything related to state management?
EDIT: I've tried using useReducer instead of useState in the custom hook and things are working perfectly now. My question is what makes useReducer work and not useState because both these hooks do the same thing. Is it because of the complexity of data structure of product details?
The custom hook for fetching product details using useState
import { db } from "../../firebaseConfig";
import { collection, getDocs } from "firebase/firestore";
import { useState, useEffect } from "react";
interface ProductDetails {
name: string;
imageURLs: string[];
rating: number;
reviewsCount: number;
monthlySalesCount: number;
isBestseller: boolean;
listPrice: number;
discount: number;
shippingPrice: number;
Color: string[];
productDescription: string[];
dateFirstAvailable: Date;
}
interface Data {
id: string;
data: ProductDetails[];
}
const useProductDetails = () => {
const [productDetails, setProductDetails] = useState<Data[]>([]);
const [loading, setLoading] = useState(true);
useEffect(() => {
const fetchProductDetails = async () => {
try {
// Fetch all categories from the products collection.
const productCategories = collection(db, "products");
const productDocumentsSnapshot = await getDocs(productCategories);
// An array to store product details
const productsData: Data[] = [];
// Iterate over each document in the products collection.
for (const productDoc of productDocumentsSnapshot.docs) {
const productId = productDoc.id;
// For each product category, fetch all documents from the productslist subcollection.
const productListCollection = collection(
db,
`products/${productId}/productslist`
);
const productsListSnapshot = await getDocs(productListCollection);
// Map over the documents in productslist to extract ProductDetails data.
const productDetails: ProductDetails[] =
productsListSnapshot.docs.map(
(detailDoc) => detailDoc.data() as ProductDetails
);
// Push an object with id and data to productsData.
productsData.push({
id: productId,
data: productDetails,
});
// Update the productDetails state with the fetched data.
setProductDetails(productsData);
console.log("Updated products state:", productsData);
}
} catch (error) {
console.error("Error fetching products:", error);
} finally {
setLoading(false);
}
};
fetchProductDetails();
}, []);
return { loading, productDetails };
};
export default useProductDetails;
The custom hook for fetching product details using useReducer & this worked!
import { useReducer, useEffect } from "react";
import { db } from "../../firebaseConfig";
import { collection, getDocs } from "firebase/firestore";
interface ProductDetails {
name: string;
imageURLs: string[];
rating: number;
reviewsCount: number;
monthlySalesCount: number;
isBestseller: boolean;
listPrice: number;
discount: number;
shippingPrice: number;
Color: string[];
Size?: string;
Style?: string;
Pattern?: string;
Brand: string;
earPlacement?: string;
formFactor?: string;
noiseControl?: string;
impedance?: number;
compatibleDevices?: string;
specialFeature?: string;
productDescription: string[];
dateFirstAvailable: Date;
}
interface Data {
id: string;
data: ProductDetails[];
}
interface State {
productDetails: Data[];
loading: boolean;
error: string | null;
}
type Action =
| { type: "FETCH_PRODUCTS_REQUEST" }
| { type: "FETCH_PRODUCTS_SUCCESS"; payload: Data[] }
| { type: "FETCH_PRODUCTS_FAILURE"; payload: string };
// Define initial state
const initialState: State = {
productDetails: [],
loading: true,
error: null,
};
// Define reducer function
function productDetailsReducer(state: State, action: Action): State {
switch (action.type) {
case "FETCH_PRODUCTS_REQUEST":
return {
...state,
loading: true,
error: null,
};
case "FETCH_PRODUCTS_SUCCESS":
return {
...state,
loading: false,
productDetails: action.payload,
};
case "FETCH_PRODUCTS_FAILURE":
return {
...state,
loading: false,
error: action.payload,
};
default:
return state;
}
}
// Fetch products function
const fetchProductDetails = async (dispatch: React.Dispatch<Action>) => {
dispatch({ type: "FETCH_PRODUCTS_REQUEST" });
try {
const productCategories = collection(db, "products");
const productDocumentsSnapshot = await getDocs(productCategories);
const productsData: Data[] = [];
for (const productDoc of productDocumentsSnapshot.docs) {
const productId = productDoc.id;
const productListCollection = collection(
db,
`products/${productId}/productslist`
);
const productsListSnapshot = await getDocs(productListCollection);
const productDetails = productsListSnapshot.docs.map(
(detailDoc) => detailDoc.data() as ProductDetails
);
productsData.push({
id: productId,
data: productDetails,
});
}
dispatch({ type: "FETCH_PRODUCTS_SUCCESS", payload: productsData });
} catch (error: any) {
dispatch({ type: "FETCH_PRODUCTS_FAILURE", payload: error.message });
}
};
// Custom hook
const useProductDetails = () => {
const [state, dispatch] = useReducer(productDetailsReducer, initialState);
useEffect(() => {
fetchProductDetails(dispatch);
}, []);
return {
loading: state.loading,
productDetails: state.productDetails,
error: state.error,
};
};
export default useProductDetails;
The code for rendering the product card
import StarRating from "../sidebar/StarRating";
import KeyboardArrowDownIcon from "@mui/icons-material/KeyboardArrowDown";
import useProductDetails from "../../useProductDetails";
import RenderColourOptions from "../../RenderColourOptions";
import { Link } from "react-router-dom";
import useFetchCountry from "../../../useFetchCountry";
interface ProductListProps {
id: string | undefined;
}
function ProductCard(props: ProductListProps) {
const { loading, productDetails } = useProductDetails();
const { country } = useFetchCountry();
if (loading) {
return <p>Loading...</p>;
}
const calculateDiscountedPrice = (
listPrice: number,
discount: number
): string => {
const discountedPrice = (listPrice - listPrice * (discount / 100)).toFixed(
2
);
return discountedPrice;
};
const renderFormattedPrice = (price: string | number) => {
const priceString = typeof price === "number" ? price.toString() : price;
const [wholeNumber, fractional] = priceString.split(".");
return (
<>
<span className="text-clamp16 ">{wholeNumber}</span>
{fractional === "00" ? null : (
<sup>
<span className="text-clamp6 align-super">{fractional}</span>
</sup>
)}
</>
);
};
const formatSalesCount = (num: number) => {
if (num >= 1000) {
const formattedSalesCount = new Intl.NumberFormat("en-US", {
notation: "compact",
}).format(num);
return `${formattedSalesCount}+`;
} else return num;
};
const calculateDeliveryDate = () => {
const currentDate = new Date();
currentDate.setDate(currentDate.getDate() + 20);
return currentDate.toLocaleString("en-US", {
weekday: "short",
month: "short",
day: "numeric",
});
};
return (
<>
{productDetails.map((product) => {
if (product.id === props.id) {
return product.data.map((details) => (
<div
key={product.id}
className="mr-[1%] mb-[1%] flex border-[1px] border-gray-100 rounded-[6px]"
>
<div className="bg-gray-100 w-[25%] rounded-l-[4px]">
<img
src={details.imageURLs[0]}
alt={details.name}
className="mix-blend-multiply py-[15%] px-[5%]"
key={details.name}
/>
</div>
<div className="bg-white w-[75%] rounded-r-[4px] pl-[1.5%]">
<Link to="">
<h1 className="text-clamp15 my-[0.75%] line-clamp-2">
{details.name}
</h1>
</Link>
<div className="flex items-center -mt-[0.75%]">
<StarRating
rating={details.rating}
fontSize="clamp(0.5625rem, 0.2984rem + 1.1268vi, 1.3125rem)"
/>
<KeyboardArrowDownIcon
style={{
fontSize:
"clamp(0.375rem, 0.1109rem + 1.1268vi, 1.125rem)",
}}
className="-ml-[1.75%] text-gray-400"
/>
<p className="text-clamp11 text-cyan-800 font-sans">
{details.reviewsCount.toLocaleString()}
</p>
</div>
<p className="text-clamp13 text-gray-700 mb-[1%]">{`${formatSalesCount(
details.monthlySalesCount
)} bought in past month`}</p>
<div className="flex items-baseline">
<p>
{details.discount ? (
<>
<sup>
<span className="text-clamp10 align-super">$</span>
</sup>
{renderFormattedPrice(
calculateDiscountedPrice(
details.listPrice,
details.discount
)
)}
</>
) : (
<>
<sup>
<span className="text-clamp10 align-super">$</span>
</sup>
{renderFormattedPrice(details.listPrice)}
</>
)}
</p>
{details.discount ? (
<p className=" text-clamp13 text-gray-700 ml-[1%]">
List:
<span className="line-through ml-[5%]">
${details.listPrice}
</span>
</p>
) : null}
</div>
<p className="mt-[1%] text-clamp13">
Delivery{" "}
<span className="font-bold tracking-wide">
{calculateDeliveryDate()}
</span>
</p>
<p className="text-clamp1 mt-[0.5%]">Ships to {country}</p>
<button className="bg-yellow-400 px-[1.75%] py-[0.5%] mt-[1%] rounded-[25px] text-clamp10">
Add to cart
</button>
<RenderColourOptions colors={details.Color} />
</div>
</div>
));
}
return null;
})}
</>
);
}
export default ProductCard;
The difference appears to be that your useState-based useProductDetails calls setProductDetails inside the loop over productDocumentsSnapshot.docs whereas the useReduce-based hook does dispatch with the productData after the loop.
This is causing an issue because you setProductDetails is called with the same productsData every time. React will assume that the state has not actually changed, and will not re-render your component. It will not look inside the array to check whether contains different elements than before. To fix this,
pushing to the same one, like productsData = [...productsData, { id: productId, data: productDetails }];