How Virtual DOM Works in ReactJS to Boost Performance and Optimize Rendering Efficiency?

User engagement can break or make the performance of applications in today’s dynamic web environment. For the same, ReactJS Virtual DOM comes into the scene and intelligently performs User Interface updates by reducing actual DOM manipulation. With the correct skills in ReactJS and how Virtual DOM works, one can build amazingly fast apps that keep users coming back to them.

If we look into the real success gained by Virtual DOMs, Twitter Lite is a perfect example. It cut down the data usage by 30% while increasing the number of pages per session by 65%. So, this optimization technique is really important in web development to make it more efficient and faster.

ReactJS Virtual DOM Explained

The Virtual DOM is a magic system for web performance- it creates a virtual copy of the real DOM in memory. React Virtual DOM is designed to update the web page faster by making timely React Version Upgrade as well as updates in the memory before making them on the actual web page.

🚀 The Virtual DOM is revolutionizing web development by enhancing performance and simplifying coding. It allows faster updates without direct DOM manipulation, making frameworks like React and Vue more efficient. Essential for modern devs! #WebDevelopme… https://t.co/vlU6pFlj8j

— prod42net (@prod42net) November 28, 2024

Virtual DOM vs Real DOM: The Performance Battle

In complex applications, traditional real DOM Document Object Model updates require re-resizing the whole page, which stifles performance. However, ReactJS Virtual DOM realizes where the React updates have to be made, and when they need to be made and therefore, it is way faster and more efficient.

Look at the example of Virtual DOM optimization:

import React, { useState } from 'react';

function Counter() {

  // Set initial count state

  const [count, setCount] = useState(0);

  // Increment count on button click

  const increment = () => {

    setCount(count + 1);

  };

  return (

    <div>

      <h1>Counter: {count}</h1>

      <button onClick={increment}>Increment</button>

    </div>

  );

}

export default Counter;

Breaking Down:

Virtual DOM Creation: React renders the initial Virtual DOM object with a count equal to 0 when this component loads.

State Update: Every time the user hits the ‘Increment’ button, it updates the ‘count’ in the Virtual DOM

Efficient Update: Then React creates a comparison between the old Virtual DOM and the new Virtual DOM tree, and only the React elements count changes, so it only changes that element in the real DOM.

Creation and Maintenance in React

• As the program is set up, React deploys a lightweight duplication of the user interface in memory. This Virtual DOM acts as a reference implementation. 
• Every time the state is updated, the complexity algorithm of React compares the changed new Virtual DOM to its previous Virtual DOM tree.  
• Like most libraries in this class, React has an intelligent process of determining which of the changes towards the Real DOM has to be applied.

Understanding the Working of ReactJS Virtual DOM

Initial Virtual DOM Setup

Process: Upon app launch, React forms a Virtual DOM that is an abstract representation of the actual DOM, stored in memory.

Benefit: The Virtual DOM allows rendering a page faster since the real DOM is not directly worked upon; React can handle the entire app interface.

<h1>Hello, World!</h1>

React stores this <h1> element and updates the real DOM with it, only once.

Handling State Changes

Process: If the data changes (i.e. user interaction) React makes a version of the new Virtual DOM representation reflecting those changes that occurred.

Benefit: To avoid immediate real DOM changes (which are slow operations), React works with an updated Virtual DOM first.

const [count, setCount] = useState(0);

const increment = () => setCount(count + 1);

When the button gets clicked, the count is updated and a new Virtual DOM is created with the new count value.

Smart Difference Detect

Process: React Virtual DOM diffing algorithm compares the new Virtual DOM with the previous version, identifying only the nodes that have been changed.

Benefit: React is popular & smart; it saves your processing power by identifying which part of the DOM changed and only updates that, firing re-rendering only where necessary.

When the count changes from 0 to 1, only the corresponding <h1> element displaying the updated count is marked for update.

Optimization through Reconciliation

Process: Once the change is identified, React figures out the minimum changes needed to the real DOM.

Benefit: React increases app performance by leveraging the crucial ReactJS performance optimization techniques and applying the fewest changes it can. This results in smoother transitions and faster page interactions.

The real DOM only has the count display (<h1>Counter:1</h1>) modified, while the button element stays the same.

Precise DOM updates

Process: React applies the calculated changes to the real DOM once the calculated changes are done.

Benefit: This targeted update process avoids reloading and re-rendering the entire page, making the application more responsive and with shorter load times.

Complete React Code Example:

import React, { useState } from 'react';

function Counter() {

  const [count, setCount] = useState(0);

  const increment = () => setCount(count + 1);

  return (

    <div>

      <h1>Counter: {count}</h1>

      <button onClick={increment}>Increment</button>

    </div>

  );

}

export default Counter;

Performance Advantages of the Virtual DOM in React

Reduces Interaction With DOM

Among the numerous advantages of React Virtual DOM, we cut down on expensive direct DOM operations. By creating a lightweight memory blueprint, rendering is brisk and interactions are smoother.

Efficient Rendering through Diffing

Smart UI updates are best illustrated by the diffing algorithm in React.  It meticulously compares Updated Virtual DOM versions and implements only the necessary elements. This targeting technique does not cost the system resources and ensures optimal performance in data-rich interfaces.

Reduced Memory Usage

The Virtual DOM is lightweight. The ability of React to work with incredibly small amounts of memory is the main reason why it operates so efficiently as it maintains a basic user interface in memory representation. This kind of efficiency is needed in memory-limited environments e.g., mobile.

Enhanced Interactive Experience

Fluid and responsive user interaction is possible using React Virtual DOM architecture. The Virtual DOM ensures that users typing forms, clicking buttons, or scrolling contents provide feedback instantly without compromising performance.

Batching of Updates

ReactJS Virtual DOM uses the Batch Updates method where instead of immediate DOM updates, it consolidates the multiple changes as a single and efficient operation. This batch Updates strategy has the least performance overhead and smoother transitions in states, which makes React great fit for enterprise -level applications.

High-Traffic Applications Ready

Under load, React Virtual DOM absolutely shines — it has proven itself to be efficient and reliable, with great performance on major platforms. Specially built for high-traffic usage and is fully capable of handling millions of connections at once. This same capability is used by social media giants to deliver reliable performance at a large scale.

Consult with eSparkBiz – a Reputed ReactJS Development Company in the market delivery exceptional Solutions leveraging React Virtual DOM

Best Practices and Real-Life Use of React Virtual DOM

Facebook

React’s creator, Facebook, proves the power of React Virtual DOM for handling data at scale. They have millions of real-time updates (From News Feed Refresh to Instant Notification) which shows how React Virtual DOM is good for handling complex and interacting interfaces.

Instagram

Instagram uses Virtual DOM to update stories/messages instantly. This is a perfect example of how they deal with such media-rich content as well as with smooth performance in the modern social platform.

Airbnb

ReactJS Virtual DOM helps Airbnb deliver instantaneous updates of listing availability and pricing changes. This implementation will help the travelers get the requirements in real-time and without having page refreshes and it will be a smooth booking experience.

WhatsApp Web

WhatsApp Web’s lightning-fast message delivery is powered by the React Virtual DOM. Therefore, with the React best practices to optimize the DOM updates, the platform seamlessly manages to achieve consistent performance, even when experiencing heavy chat sessions and media transfers.

Netflix

The Virtual DOM is used by Netflix for its video player interface. This allows for smooth episode transitions, keeping quality high with excellent control, and responsive user controls.

Twitter Lite

The most exciting success story comes from Twitter Lite. Their implementation of the React Virtual DOM showed great improvements: A decrease of 30% in data consumption and an increase in page views per session by 65%. This Digital transformation shows that good DOM management can change user engagement and resource usage drastically.

Improving Rendering Speed through ReactJS Virtual DOM

Understanding the UI with Component-based Architecture

Modular design supports the React Virtual DOM. Therefore, you can concentrate more on the React components as well as make smaller updates so that only the changed section of your application is being updated. These changes in React component-based architecture reduce the event of unnecessary re-rendering.

Using Pure Components to Render Specific React Re-renders

React DOM automatically optimizes the rendering process using Pure Components. Virtual DOM in React can avoid updates of web components that are not changed on a prop and state basis, and this is good for high-density apps.

Functional Components Performance Improvement with React.memo

Instead of using shouldComponentUpdate, React. memo is more of an advanced optimization technique that detects unnecessary re-rendering in stable React components. This is where this technique shines when React components are not updated very often but they have a lot of parent updates.

Strategic State Management

Virtual Document Object Model efficiency depends highly on careful state placement. Minimizing the use of Global state management tools and localizing state change will prevent cascade React updates therefore enhancing performance.

Class Component Optimization

shouldComponentUpdate gives you more control of the Virtual DOM’s update cycle than for class components. It avoids setting up unnecessary React diffing processes, which otherwise would consume computational resources.

On-Demand Component Rendering

Lazy loading patterns fit into ReactJS Virtual DOM. On-demand loading of reusable web components decreases the time and memory for rendering when the application is first launched, especially in complex applications.

Implementation of Unique Keys in the List

In case the keys are properly implemented in the list, the Virtual DOM can trace the changes commendably. It is quite simple and greatly improves the updating performance whenever dealing with dynamic collections.

Chintan Gor

CTO, eSparkBiz

Enthusiastic for web app development, Chintan Gor has zeal in experimenting with his knowledge of Node, Angular & React in various aspects of development. He keeps on updating his technical know-how thus pinning his name among the topmost CTO's in India. His contribution is penned down by him through various technical blogs on trending tech. He is associated with eSparkBiz from the past 14+ years where one can get premium services.