Tips for optimizing React performance in 2024

Quick Summary:

When working with a React JS application, developers and product owners frequently worry about performance problems. They are unable to utilize React framework’s magnificent advantages because of this unpopular belief. However, by focusing on performance optimization in React, you may take advantage of the many benefits of this cutting-edge frontend framework once you comprehend how and why React apps execute slowly as well as how to improve React speed. This article discusses the top methods for improving the performance of React apps so that you can overcome the dangers and difficulties.

Introduction

• No user will want to waste their time on a web application that requires excessive patience from them. Time is a valuable resource. React is a well-liked framework that programmers trust for fast rendering. React is used by well-known companies like LinkedIn, DropBox, CSDN, Baidu, and others because of this.

• Developers can intelligently and actively ensure React.js performance optimisation approaches by taking a few key measures into consideration and indicating them. React, however, even renders many irrelevant components resolving such speed difficulties.

React Performance: How UI is rendered in React?

• Your user interface (UI) in React is generated by modifying something known as the DOM (Document Object Model). DOM resembles a tree-like structure of objects and nodes in simple layman words.

• However, HTML is not a DOM root node in React. Actually, the Javascript prototype chain’s prototype node that gets the functions to compute styles, properties, or manipulate individual nodes is the sole one in the chain.

• To put it simply, DOM in React is a standard that specifies how you can obtain, modify, or work with HTML components. The React DOM is capable of rendering pages, but it lacks the intelligence to monitor each node and component that is changing.

• Let’s imagine you have a list of ten things on your single page application (SPA), and you need to change one of them whenever a user interacts with the user interface. With DOM, you will ultimately update every component because the full list will be rendered again. This is where the idea of virtual DOM is useful. The HTML DOM is replicated locally by React as the Virtual DOM.

• Returning to our list example, let’s see how Virtual DOM will enable React to render the UI. React would make a copy of the UI when a user interacted with it in the form of a virtual DOM and update the UI after comparing the virtual and actual DOMs. This will allow the changed item to be applied without affecting other items.

React js Performance – What’s BAD about Virtual DOM?

• You have read about the benefits of Virtual DOM in the section above. Let’s now become familiar with the problematic aspects of the Virtual DOM, which are solely to blame for many of React’s performance concerns.

• React uses a diff method to reduce the number of operations that must be performed at nodes. The algorithm itself, though, is not flawless. Consider the GIF below, which depicts what appears to be a react DOM tree. Let’s imagine that the nodes highlighted in yellow need to have their values updated because they have changed.

• As you can see above, React renders all of the subtrees rather than just the appropriate component. These pointless renders can chew up needless CPU and memory resources when they are inactive in a React application, which can be disastrous for your React application. They are known as Wasted Renders for this reason.

Virtual-DOM is where around half of Reactjs’ performance-related issues are caused.

• Redundant operations in parts that don’t modify the DOM

• Leaf nodes that don’t need to be updated are continually updated using the Diff Algorithm

• Heavy CPU processing caused by components of the Diff algorithm updating

Let’s examine how to improve the performance of a React app now that we are aware of the reason of performance glitches in React.

Proven Ways to Improve & Boost React Performance

• Making incorrect async calls when you write React code over time leads to a rise in the bundle size of a React-based progressive web application. The longer loading time of the React application is a direct result of the larger bundle size.

• The build size of the programme can be optimised using a few tools and tricks, nevertheless, to reduce the loading time. To get around the expensive DOM operations, there are excellent React performance optimization approaches that we suggest. Discover how. To get around the expensive DOM operations, there are excellent React performance optimisation approaches that we suggest. Discover how.

1. Windowing or List Virtualization in React Applications

• The performance of many React applications that use or display lengthy lists is frequently problematic. The complete list will be rendered in the DOM prior to loading the app, significantly slowing down the React.js app’s performance and generating UI latency.

• List Virtualization or Windowing is one method for getting around this problem. Here, we only permit a limited list of objects to be rendered on the DOM as much is visible, as opposed to presenting the entire long list of components on the app screen.

• React-window and react-virtualized are the two windowing libraries that are available; you will enable rendering a small portion of the lengthy list on the app screen. The performance of your React app will change.

2. Key Coordination for List Rendering

• When working with lists in React, you can give an element important properties that will aid in rendering the following elements. If the developer incorrectly assigns component keys to list elements for dynamic lists, it becomes useful for the user and slows down the speed of the React app. Here, it is unnecessary because the new list entry will immediately recommend the prior list entry.

• To address this bottleneck, you must give each list component a distinct key value. To improve the efficiency of your dynamic lists in a React project, use Key={}.

3. Lazy loading Images in React

• There is a good probability that your React app’s performance will suffer if it has a lot of photos. This occurs because the DOM renders each image individually before presenting the user interface. Therefore, we advise employing lazy loading images, which only render that specific image after waiting until its turn has appeared on the user’s screen.

• Similar to how windowing prevents extra DOM nodes from being created, lazy loading of images does the same. React-lazyload and react-lazy-load-image-component are the two widely used libraries for lazy loading to improve React speed.

4. Functional Components & Component Interaction

• By leveraging functional components, React applications can be performed more efficiently. The easiest and tried-and-true method for quickly creating effective and performant React apps, despite its cliched sound.

• When using Components, our React experts have some recommendations. Keeping your components minimal is advised by our skilled React developers because they are simpler to read, test, manage, and reuse.

• React components, such as the React Devtools (extension), provide the following benefits: • Less code is needed; • Easy to comprehend; • Components are stateless; • Easy to test; • Flexibility to extract smaller components; and • Interactivity.

Also Read: 7 Advantages of ReactJs for building interactive user interfaces

5. Understand How to Handle ‘this’

While ‘this’ binding is not necessary for functional components, you may want to use them whenever possible. React will not automatically bind your functions within components if you are using ES6 binding, though. You can still manually achieve the binding, though. You can bind your components and functions in the following ways:

• Rendering with binding
• Embrace the arrow function in rendering
• Binding in the constructor
• Bind the class’s attribute to the arrow function. [Not in the authorized ECMAscript]

6. Use a Function in ‘SetState’

In the setState function, we advise against using an object but rather a function. This advice is given because, as stated in the React documentation, state changes aren’t always indicated instantly. In place of this, then:

this.setState({correctData: !this.state.correctData});

Use as follows:

this.setState((prevState, props) => {
    return {correctData: !prevState.correctData});
  }

The previous state and the props at the time the update is applied are passed as arguments to the aforementioned function, respectively.

7. Utilize Prop-Types

A library for type-checking props is called prop-types. You can import the method from the prop-type library using the code snippet below:

import PropTypes from 'prop-types';

class Welcome extends Component { 
   render() {
     return <h1>Hello, {this.props.name}</h1>;
   }
  }

 Welcome.propTypes = {
    name: PropTypes.string.isRequired
  }

8. Trim Javascript Bundles

• In React optimization, learn how to trim your Javascript packages to get rid of redundant code. Your React application’s performance has a greater chance of succeeding if you eliminate redundancies and pointless code. You need to evaluate and decide on the bundled code.

9. Server-Side Rendering (SSR)

• Consider using SSR deliberately and determining whether your application genuinely requires SEO. If you can avoid utilising SSR when it’s not necessary, you’ll be in luck. SSR consumes a tremendous amount of load.

• In terms of SSR, NextJS is the best. Developers are starting to use the NextJS-based React Admin Dashboard more and more frequently. You may easily speed up the development process with the help of NextJS’s integrated React admin templates.

10. React Redux Optimization Tips

• When React apps are created with Redux, a classic example to take into account is a well-known problem addressed by Yahoo. Yes, the combo is lethal and helps structure complex circumstances, however using Redux causes your React app to render again and slows down your speed, which is a common challenge when optimizing React applications.

• We’ll outline two strategies for using React Redux applications to get around this problem. The first one is using the RESELECT library when your React app’s higher-order components are allotted for rendering tasks. Yahoo gained a great deal from using this library.

• Utilizing Immutable.js is another way to enhance the efficiency of React Redux apps. An immutable list performed up to four times better than a mutable list. The Redux state tree uses a lot of memory to copy data when mutable data structures are used, which hurts the app’s performance.

When using an immutable data structure, whenever new data is requested, a fresh copy of the updated data structure is created rather than the original data being updated. This method significantly boosts React’s performance.

11. Improve React App Performance Using React Memo [Memoization]

• Here, we’ll go through a fundamental overview of how to use react memo for improving the efficiency of React apps.

[Note: useMemo and react.memo are not the same. Because of their similar names, these two are frequently mistaken.]

Describe React.memo.

• The render method in a react application is notoriously heavy. Are we not? The results of rendering the component without making any significant changes are known to us. In light of this, imagine a situation in which you render a class component even though your input props are the same. Is it suitable? It’s obviously not! When the input props are consistent, why in the world would you call such a complex render method? Use PureComponent or shouldComponentUpdate() in this specific situation. 

What about the functional (stateless) component? The class component’s scenario was this. React is the answer, so don’t be concerned.Memo.

High Order Component in React.memo.

• You can wrap your functional component with React.memo to improve efficiency if it consistently produces the same output since it receives the same input props. As a result, React will compare the most recent render to the current one and forgo rendering the component if there are no differences. This will make the react app run more efficiently. Your functional component can be wrapped with React.memo as demonstrated below:

const MyExampleOfMemo = React.memo(function MyComponent(props) {
  / render using props /
});

• React will compare using its default behaviour, a shallow comparison of complicated items in the props object, if you decide not to give any second arguments. The comparison is under your control if you want to pass the second option, thus you can create a unique comparison function.

function MyExampleComponent(props) {
  / render using props /
}
function equalOrNot(prevProps, nextProps) {
  /*
  It will return true if nextProps to render would return
  the same result as prevProps to render,
  otherwise return false
  */
}
export default React.memo(MyExampleComponent, equalOrNot);

• While using React.memo, use caution. Since it might produce bugs. Take a simple example to illustrate the necessity of react.Clear your mind.

Create a tiny app that calls render every second and uses setState() once every second. We are aware that this is not possible, but I’m simply trying to explain why React.memo is necessary.

class App extends Component {
  cities = ["Mumbai", "Banglore", "Delhi"];
  state = { city: "Anonymous" };

  componentDidMount() {
    setInterval(() => {
      const city = this.generateCity();
      this.setState({ city });
    }, 1000);
  }

  generateCity = () =>
    this.cities[Math.floor(Math.random() * this.cities.length)];

  render() {
    return < View city="Kolkata" />;
  }
}

• Here, we can see that in componentDidMount(), we called the setInterval method. We have another function called generateCity() for this purpose, which does indeed set the city name from the array of cities.

• The component will be re-rendered every second as a result of the setState() function being called every second, which is something to keep in mind. Therefore, even though the city is hard coded, our View component also renders. Is it practical? Obviously not.

const View = ({ city }) => `City name :: ${city}`;

• This is not logical. If the props remain the same, why would we re-render a component (in this case, the View component)?

• Now that we have knowledge of the idea of memorization from the previously provided material. If the value of the props remains constant, we may use React.memo to prevent the component from rendering.

Let’s enclose the component “View” in a memo.

• Now that we have knowledge of the idea of memorization from the previously provided material. If the value of the props remains constant, we may use React.memo to prevent the component from rendering.

Let’s enclose the component “View” in a memo.

import { memo } from 'React';

const View = memo(({ city }) => `City name :: ${city}`);

• Now that the value of prop city remains constant, we can see that the View / > component will only render once.

• When the prop was hardcoded, this was the circumstance. See what happens if we choose to use the state value instead of the hardcoded value.

• The city value is randomly selected from the array of cities in the generateCity() function.

• The view component won’t render anytime the city is given the same value because the city prop will logically hold the same value.

• Keep useMemo and React.memo distinct from one another. Don’t judge them by their names; each one of them serves a different purpose. We may say that useMemo and React.memo both make utilise of the idea of memorization while maintaining their unique identities.

• React.memo enhances the functionality of a react application by managing how different components are rendered. You can decide whether to render a component in its entirety.

• UseMemo, however, doesn’t offer the same level of comprehensive management. It is intended to return memoized value and is used for more broad purposes. The useMemo hook contains broad usage guidelines. React is the key message.Memorise renders where prop doesn’t change to optimise the react application. However, exercise caution when improving performance because it might lead to bugs.

Conclusion

We hope you will follow and put into practise the React app performance optimization advice that we have offered in this blog now that you have a clear understanding of React performance challenges and React performance techniques. Improve the efficiency of your current React application by working with the top Reactjs development company, who can offer experienced advice and best practises.

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