In development, precision is non-negotiable. You have an App that efficiently displays products based on a server-side render. It's all working smoothly until you introduce a "Clear Selections" button that should fetch the same products—only to find out that they're not in the expected order.
This post addresses two crucial questions:
The Challenge: Why does the order of products differ between the server-side render and the client-side fetch call?
Set and Map: What are these essential tools that helped us solve this issue?
Let's get straight to the heart of the matter. We'll explore the challenge and explain Set and Map in the context of resolving order discrepancies in product rendering.
The Challenge:Server-Side vs. Client-Side Rendering
You've developed a web page that efficiently renders products on the server side, following a well-structured query. However, the introduction of a "Clear Selections" button triggers a client-side fetch call to fetch the same products, but they end up in a different order.
This discrepancy arises due to the inherent differences between server-side and client-side rendering processes. Server-side rendering is often deterministic, while client-side rendering can introduce asynchrony, resulting in products appearing out of order.
Set and Map:
In JavaScript, Set is a data structure that stores a collection of unique values, ensuring there are no duplicates. You can learn more about Set on MDN.
On the other hand, Map is a data structure that allows you to store key-value pairs, providing efficient look-up and retrieval. Find detailed information about Map on MDN.
A Set and Map Solution
After pondering on how to resolve the order discrepancy between server-side and client-side rendering, a lightbulb moment struck. I recalled an article discussing the prowess of JavaScript's Set and Map data structures, and I decided to put them to the test.
Here's how I tackled the issue, presented through a simplified example:
// Step 1: Create an empty Set and Map
const productSet = new Set();
const serverRenderedOrder = new Map();
// Step 2: Populate the Set and Map during server-side rendering
function serverSideRender() {
const products = fetchProductsFromServer(); // Fetch products from the server
products.forEach((product, index) => {
productSet.add(product.id); // Add product IDs to the Set
serverRenderedOrder.set(product.id, index); // Store the original order in the Map
});
}
// Step 3: During client-side rendering, use Set and Map to maintain order
function clientSideRender() {
const products = fetchProductsFromClient(); // Fetch products on the client side
const sortedProducts = [];
products.forEach((product) => {
const productId = product.id;
const originalOrder = serverRenderedOrder.get(productId);
if (originalOrder !== undefined) {
sortedProducts[originalOrder] = product; // Sort products based on original order
}
});
return sortedProducts;
}
Explaining the Code
To resolve the order discrepancy challenge between server-side and client-side rendering, we implemented a solution utilizing JavaScript's Set and Map data structures. Here's a breakdown of the code:
Step 1: Create an Empty Set and Map
const productSet = new Set();
const serverRenderedOrder = new Map();In this step, we initialize two crucial data structures.
productSet is a Set that stores unique product IDs. serverRenderedOrder is a Map that preserves the original order of products during server-side rendering.
Step 2: Populate the Set and Map during Server-Side Rendering
function serverSideRender() {
const products = fetchProductsFromServer(); // Fetch products from the server
products.forEach((product, index) => {
productSet.add(product.id); // Add product IDs to the Set
serverRenderedOrder.set(product.id, index); // Store the original order in the Map
});
}
During server-side rendering, we fetch the products and iterate through them. For each product, we:
Add its unique ID to the productSet to ensure no duplicates. Use the serverRenderedOrder Map to store the product's ID along with its original order index.
Step 3: Maintain Order during Client-Side Rendering
function clientSideRender() {
const products = fetchProductsFromClient(); // Fetch products on the client side
const sortedProducts = [];
products.forEach((product) => {
const productId = product.id;
const originalOrder = serverRenderedOrder.get(productId);
if (originalOrder !== undefined) {
sortedProducts[originalOrder] = product; // Sort products based on original order
}
});
return sortedProducts;
}
During client-side rendering, we fetch products and create an array called sortedProducts to maintain the correct order. For each product:
We retrieve its original order index from the serverRenderedOrder Map.If the originalOrder is defined (i.e., it exists in the server-rendered order), we place the product in the corresponding position in sortedProducts.
In summary, this code utilizes Set and Map to bridge the gap between server-side and client-side rendering, ensuring that products are displayed in the correct order, ultimately resolving the order discrepancy challenge.
Conclusion: Set and Map - My Order-Fixing Allies
In my web development career, I encountered a common challenge: maintaining precise product order during rendering. Server-side and client-side rendering often disagreed.
The solution? I turned to JavaScript's Set and Map. They proved to be reliable allies, ensuring client-side products matched the server-side order.
If you found this post helpful or think it could benefit a fellow developer, please consider sharing it.
Share this article