There are lots of frameworks that help build User Interfaces. Still, of all these, ReactJS has distinguished itself in assisting the development community with the faster and more effective deployment of web projects. React JS's unique features and advantages have made it immensely popular, as the framework has collected more than 160k stars on its official GitHub repository.
Ten React Optimization Tips
This article illustrates ten React optimization tips to further enhance the technology's potential for achieving outstanding results.
Use React DevTools
Every React developer should have React DevTools ready in their backpack to analyze React applications, React components, and React subcomponents for faster debugging of identified problems. The tool is available as a browser extension for Firefox and Chrome. It makes it easy to examine the list of React components that build the page of a particular React application.
After installing and enabling the React DevTools in the browser, an additional tab, 'Components,' is added to the developer tools.
Clicking this component tab provides a convenient option to explore the React components and sub-components, highlight them, and filter them by name. This is much easier than looking at the DOM elements because the DOM tree doesn't provide much information on components and applications.
The DOM tree has an extensive codebase where the components are not individually labeled, making it difficult for a developer to debug the problem. However, the tool's components tab allows developers to view and inspect the props, state, and hooks of a component in real time to identify where exactly such a component is failing in the execution. As such, debugging becomes a less painful task, and the issues are resolved faster.
Even a Quality Analyst with operating knowledge of React DevTools will be in a much better position to report issues to the development team by highlighting the relevant component that needs attention.
Also, if a developer is interested in a specific function, like the callback function, the tool can make it available as a global variable. As such, the developer shall be able to call such functions per the requirements with different arguments. To do this, the user can right-click a particular function appearing in the props, and the option to make it available as a global variable will appear.
However, React DevTools is not limited to component analysis and debugging. It can also help with performance analysis with the Profiler.
Once the React DevTools has been enabled, the Profiler tab will be added to the Components tab in the developer tools.
Accessing the Profiler tab will show an empty environment, but there will be a record button. The developer can click on the record button to start the profiling process.
After clicking the record button, the Profiler automatically collects performance information every time the React application renders. The developer can click the stop button to end the profiling.
The Profiler executes the performance analysis, and the results can be examined via the flame graph and ranked chart.
Flamegraph: The Flamegraph demonstrates the state of the React application for a specific commit. It consists of bars that show the React component. Each bar has a color and size that demonstrates how much time was consumed to render the component and its child components.
Ranked Chart: The ranked chart view demonstrates a single commit. Every bar in the chart reflects a React Component (e.g., Suspense). The bars have been ordered so that the component that consumes the longest time to render is at the top, and the component that consumes the least time is at the bottom.
React DevTools is a practical extension used by most React developers working in the top web development companies.
Use Error Boundaries
Developers often face scenarios where component rendering results in unexpected application errors. Although a developer should never let a component error break the entire React application because such an error unmounts the components completely, nothing is left but a blank HTML page. This leaves the developer confused and on an unclear path. However, such a situation can be avoided with Error Boundaries in practice.
Error Boundaries help the developer identify and catch JavaScript errors anywhere in the child components tree. It also displays the fallback interface (not the components tree that has crashed), which makes it easy to work on the errors.
Error Boundaries in the React framework are class components that define one or both of the following lifecycle methods-
1. static getDerivedStateFromError()
2. componentDidCatch()
The first lifecycle method, static getDerivedStateFromError(), renders the fallback user interface if an error has been encountered. The second lifecycle method, componentDidCatch(), logs error details to an error monitoring tool like Sentry or Crashlytics.
After that, the developer can use it as a regular component.
However, there are some essential things about Error boundaries that a developer should know:
Only class components can be labeled as Error boundaries
Error boundaries capture the errors in only those components that fall below them in the tree
An error boundary can't capture the error within itself
Use React & TypeScript
Using React and TypeScript together is a powerful combination that every React developer should follow in their coding practice. This combination is not only a replacement for React PropTypes but also brings a lot of other beneficial opportunities for the React ecosystem, as illustrated below:
- Faster Application Development: The accurate Intellisense of TypeScript offers much help in rapid app development. The leading IDEs in today's date, like Atom, Visual Studio, WebStorm, NetBeans, etc., feature many competitive features like support for code completion, better auto-completion, and better snippet-generation. Hence, all these strong IDEs are brought into the development environment when React and TypeScript are used together, which results in a faster app development experience.
- Robust Interfaces: TypeScript offers a strong interface to React JS developers for activating complex type definitions. This is a helpful feature in scenarios where the developer has a complex type and wants to utilize it in an application. Using Interfaces also executes strict and in-time checks that reduce the number of expected bugs that might have been generated if the Interface were not used. Hence, code quality is achieved when React and TypeScript are used together.
- Several Declaration Files: TypeScript has an extensive community that regularly releases many declaration files for widely popular JavaScript libraries. These declaration files help the development communities merge React with TypeScript to leverage the benefits of various useful JavaScript libraries.
- Refactoring Features: TypeScript allows Visual Studio Code to stage refactoring to a whole new level. For example, if a developer tries to rename a particular component in a JavaScript React application, Visual Studio could automatically rename the references in the same file, although not in different files. But if TypeScript is used, then the developer shall get the references automatically across the entire codebase.
- Next-level Code Navigation: Navigating through code via different files in the JavaScript React app becomes a pain for VS Code. But the go-to-definition characteristic works properly if the developer has used TypeScript.
Use Jest and Enzyme for Testing
Jest and Enzyme are two different testing tools. Still, if used together, the powerful duo can unlock creative testing abilities for the developers to improve the React application development process.
Jest is a simple JavaScript testing framework for testing React applications. For developers new to the React environment, it is recommended to use Create React App because it is pre-packaged with Jest. However, users will need to add react-test-renderer only for rendering the snapshots.
Some of the top features of Jest that label it as a popular testing tool are:
- It is lightning fast and can complete local tests in just 14.5 minutes.
- It has a comprehensive mocking library.
- In Jest, the developer can control the dependencies and master time.
- Jest can control timer-related functions like setInterval(), setTimeout(), clearInterval(), and clearTimeout()
- Jest extends complete support to ES6 classes as well as TypeScript.
- Jest can perform snapshot testing.
The Enzyme is also a JavaScript testing tool developed by Airbnb for testing React components output while leveraging the complete benefit of Virtual DOM at the same time. It offers some great utility methods for the following:
- Rendering multiple components
- Navigating the elements
- Interacting with the elements
To activate Enzyme, the developer must follow the installation instructions outlined in the Enzyme technical documentation.
For improved React JS development, the React developers of top React JS development companies use them together. Jest can be used as the test runner, mocking library, and assertion library, and then Enzyme can be brought into the picture to build the tests for the application's UI. The result is cleaner testing code that becomes easy to debug if the test breaks.
Experienced developers use them together because it makes React component testing easier, helps quickly detect bugs, and ensures that the application's User Interface looks and acts as expected.
Split the Code
The code splitting method segregates the codebase into different component bundles, individually loaded on-demand or simultaneously. It delivers only the required code for initial execution, which the developer has requested to load while using the application. It minimizes the amount of code needed to be compiled and helps load the page faster.
The single-page React apps use tools such as Webpack, Browserify, or Rollup to bundle the files together. Bundling is a method of merging imported files into a single file. The bundle on the web page can load the whole application at once.
Bundling is impressive, but the bundle will also increase as the app grows and evolves daily. When implementing third-party libraries in a bundle, it should be ensured that they don't become too large because the larger the code size, the greater the time it will take to load. Sidestep the large, unwound bundle. The developer will have to split the large bundle to get ahead of the loading problem. In code splitting, the independent domains are built for faster code loading and a better application user experience.
For this purpose, bundlers have a feature known as code splitting, which can build multiple bundles and dynamically load them quickly at runtime.
Once the code has been segregated, the developer must decide how to use the segregated code. The code-splitting helps in "lazy-loading" of the application, through which the component currently required by the developer can be loaded. Lazy loading is a technique that loads only the needed components across the user interface. It improves the overall app performance because, in this case, only that component is loaded, which is necessary for executing the required functionality demanded by the user. Meanwhile, there won't be any need to reduce the app code size. Thus, the component that is not required is not loaded, and the initial loading time is reduced.
To "lazy-load" the segregated component, the import() statement is embedded in code to import a component from another module. To call the component, the developer can declare it in the module with import(). The import parameter cannot be generated dynamically and is impossible at runtime or on condition. To import the module, it is necessary to always mention the path with a primitive string.
Lazy Loading for React
React. Lazy function enables the rendering of a dynamic import just like a regular component. The code is split into different elements, including React. Lazy loads only those components that have been requested without any help from additional libraries. It's fully integrated into the core React library.
Splitting the code is a good practice that every React developer should adopt to improve the development practice and provide users with a better experience.
Use Content Delivery Network
Using CDN (Content Delivery Network) with React applications is an innovative practice to boost the speed and functionality of the website. In the digital age, website loading speed matters a lot. If the development process is finished without recognizing this need, achieving an optimum user experience will become challenging. The result? The bounce rate will increase, and the business opportunity will be lost. Also, a slow-loading website can result in a bad ranking on the search engine results page.
It is a fact that ReactJS is pre-loaded with competitive characteristics that build a responsive website with an interactive UI for delivering a great user experience, but using the CDN can further accelerate React's potential to serve users better.
Using CDN reduces the distance between the servers and the website visitors. It places website content, such as text, images, videos, etc., on different servers worldwide and delivers it to the visitors from the nearest server. The loading speed is escalated because the time needed for the content to load is significantly reduced.
Two options make the React CDN combination possible. The first option is for organizations to use their CDN account. However, this option consumes a lot of time because the development team would have to build the library from scratch in this option.
In the second option, open-source CDN services, such as CDNJS, JSDelivr, Google Hosted Libraries, Microsoft Ajax CDN, etc., can be used to call the library. These CDN services have an extensive reach, are loaded with many libraries, and save a lot of time.
Use CSS Animation Rather Than JavaScript Animation
There are two primary ways to create web animations - CSS and JavaScript. CSS animations are used to build short and straightforward transitions, like toggling the states of the UI elements. JavaScript animation delivers advanced effects like slow motion, stop, bouncing, or rewind.
However, CSS animation is better than JavaScript animation because the former has self-contained and small UI elements. It's best to introduce a tooltip, a navigation menu on the side, and the simplest way to show movement on-screen. In a declarative approach, developers must specify what they want to make happen.
The CSS declarative approach requires cheap interpretation. To quickly display the elements on the screen, the style snaps are parallelized in memory. The style properties can be changed before the elements are painted on the screen.
CSS efficiently delivers the required design and is considered best for animations requiring transformations.
For animations, the loading cost of a JavaScript library is relatively higher than that of CSS. JavaScript consumes greater network bandwidth and high computation time.
JavaScript can provide better optimization than CSS, but the optimized JavaScript code can crash the web browser and lock the User Interface.
In CSS, the 100px element can move in the X and Y axes and takes 500ms for the transition. The move class is implemented, and the transform value is changed to show the transition on the screen. Separate classes are created to manage the animations.
CSS animations provide much more control over the animation duration and iterations. They also help change multiple properties at the same time. For example, a box can be animated with transitions without any user interaction, as shown in the snippet shared below.
Note: The specific frame to show a particular action is called the key frame. The most extreme portion of the motion is captured and fills the gap between the keyframes.
CSS animations define the animation independent of the target element, and the animation-name property is implemented to select the required animation. The animation takes place as soon as the animation property is applied. Developers can change the property value inside each particular keyframe.
CSS animations are excellent to use as almost all popular browsers support them.
Activate gzip Compression
Gzip methodology is used to compress files of any type, like plain text and images, for rapid transfers and enhanced web performance. The lossless Compression enables the web server to load the files faster on the front-end so that the website visitors can have a better experience while engaging with the website. Activating gzip Compression is a standard process, and not following it could lead to the web page loading more slowly. Gzip reduces the web file size by 50-70% of the original file and boosts the application performance. Some of the top benefits of enabling gzip include:
- Reduces page size by up to 70%
- High-cost benefit ratio
- Improves the page loading speed
- Provides an SEO advantage
Two popular methods to activate gzip have been illustrated below:
Gzip While Building
To get started, the developer can generate bundle.js.gz instead of the compression plugin bundle.js and configure gzip over the web server to initiate it. Gzip can reduce a 7MB file to just 400kb, allowing the web page to load in just a few seconds.
Dynamic Gzip
The other method is to add a compression plugin to the application, which compresses the bundle file dynamically before serving it. While compressing the files dynamically, the developer should be careful about the content.
There are various options for using a compression package for the files, but the most responsive is level. A filter can be used, which provides a predicate to indicate whether to compress a file or not. The default filter keeps a record of file size and type.
Use Web Workers
When a web page is rendered, it has to perform multiple tasks synchronously, like enabling animations, handling DOM elements, manipulating response data, directing UI interactions, and much more. Since JavaScript is a single-threaded language, it can execute a single process, affecting website performance because, to get started, one method has to wait for the completion of the earlier process. That's where the role of web workers comes into play, enabling browsers to run multiple files simultaneously with the help of worker threads.
Web Workers enable the browser to run scripts in the background and provide extra threads that can take off the workload from the main thread and execute processes separately. These extra threads are worker threads, which perform a particular task without interfering with the main thread. Thus, the execution load is reduced over the main thread.
When the system needs to execute many tasks, it puts an intensive load on the CPU. Therefore, the task is broken down into different logical units. The logical blocks that are required to be executed are placed into separate threads with the help of workers. The other threads execute in an isolated environment and use interprocess thread communication to interact with the main thread. In this way, the main thread keeps pace with the rendering and manipulation of all tasks. Hence, it is recommended that web workers be used during React development.
Save Time by Avoiding Inline Style
We often use inline functions in the render method, but we usually don't know how they affect the application's performance. By default, the render method is called every time the inline function is used, and a new function instance is created.
As we know, React uses virtual DOM to make real DOM updates. When virtual DOM diffing is performed, a new instance of the function is created for each rendering phase. A new updated function is created, and the old one is disposed of in the garbage collection. Thus, direct binding of the inline function generates extra load on the garbage collector, and the new function binds to the DOM, which leads to unnecessary DOM updates.
Avoid using inline functions and instead create a function inside the component; thus, the event is bound to the function itself. As a result, a new instance of the function is not created every time render is called. Thus, processing is reduced, and performance is improved.
Wrapping Up
React JS development has become a necessity for organizations. Whether it is a newly-established startup or a Fortune 500 corporation, this technology from Facebook has made its way to help all-scale businesses successfully expand their operations in the digital world. Implementing the ten tips above to improve the React game can further help to experience this technology's wonders. The top React JS development companies adopt these practices to provide better development services to help businesses achieve their perfection goals.
