There are lots of frameworks that help build User Interfaces. Still, of all these, ReactJS has distinguished itself to help the development community in the faster and effective deployment of web projects. The unique features and advantages of React JS have made it immensely popular as the framework has collected more than 160k stars on its official GitHub repository.
Ten React Optimization Tips
In this article, ten React optimization tips have been illustrated to further push the technology to its maximum potential for achieving outstanding results.
Use React DevTools
Every React developer should have React DevTools ready in the 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 and makes it easy to examine the list of react components tree that has built the page of a particular react application.
After installing and enabling the React DevTools in the browser, it adds an additional tab, ‘Components,’ in the developer tools.
Clicking this component tab provides a convenient option to not only explore the React components and sub-components but also highlight them and filter them by names. It is much easier than looking at the DOMs elements because the DOM tree doesn’t provide much information on components and applications.
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 component is failing in the execution. As such, debugging becomes a less-painful task, and the issues are resolved faster.
Even a Quality Analyst having the operating knowledge of the 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, then the tool can be used for making such function available as a global variable. As such, the developer shall be able to call such functions as per the requirements with different arguments. To do this, the user can right-click a particular function appearing in the props, and the option for making it available as a global variable would appear
However, React DevTools is not just limited to the components analysis and debugging. It can also help in performance analysis with the help of Profiler.
Once the React DevTools has been enabled, then it also adds the Profiler tab adjacent to the Components tab in the developer tools.
While accessing the Profiler tab, it 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 shall automatically start collecting the performance information every time the React application renders. To end the profiling, the developer can click on the stop button.
The Profiler executes the performance analysis, and the results of such analysis can be examined via the flame graph and ranked chart.
Flamegraph: The Flamegraph demonstrates the state of the React application for a specific commit. The flame chart 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 children components.
Ranked Chart: The ranked chart view demonstrates the single commit. Every bar in the chart reflects a React Component (e.g., Suspense). The bars have been ordered in such a way so that the component that consumes the longest time to render comes at the top and the component that consumes the least time comes at the bottom.
React DevTools is an effective and pragmatic extension used by most of the React developers working in the top web development companies.
Use Error Boundaries
The developers often face scenarios where the component rendering results in an unexpected error in the application. Although a developer should never let a component error break the entire react application because such an error unmounts the components completely, there is nothing left but a blank HTML page. This leaves the developer with confusion and an unclear path. However, with Error Boundaries in practice, such a situation can be avoided.
With the help of Error Boundaries, the developer can identify and catch the JavaScript errors located anywhere in the child components tree. Also, it 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(), is used for rendering the fallback user interface if an error has been encountered. The second lifecycle method, componentDidCatch(), is used to log 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 important 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 the coding practice. This combination is not only a replacement for React PropTypes but brings a lot of other beneficial opportunities for the React ecosystem, as illustrated below:
- Faster Application Development: The accurate Intellisense of TypeScript offers a lot of help in faster app development. The leading IDEs in today’s date, like Atom, Visual Studio, WebStorm, NetBeans, etc., features a lot of 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 robust 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 quantum of expected bugs that might have been generated if Interface was not put into use. Hence, code quality is achieved when React and TypeScript are used together.
- Several Declaration Files: TypeScript has an extensive community that regularly release a lot of declaration files for widely-popular JavaScript libraries. These declaration files help the development communities to merge React with TypeScript for leveraging the benefits from various useful JavaScript libraries.
- Refactoring Features: TypeScript provides the Visual Studio code with an opportunity to stage refactoring to a whole new level. For example, if a developer will try to rename a particular component in JavaScript react application, then Visual Studio would be able to rename the references automatically in the same file, although not in the different fields. But if TypeScript is put into use, then the developer shall get the references automatically all across the entire codebase.
- Next-level Code Navigation: Navigating through a code via different files in the JavaScript React app becomes a pain for the VS code. But Go to definition characteristic works properly if the developer has put TypeScript into use.
Use Jest and Enzyme for Testing
Jest and Enzyme are two different testing tools. Still, if used together, then 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 that can be used for testing React applications. For the developers new to the React environment, it is recommended to use the Create React App because it is pre-packaged with Jest. However, for rendering the snapshots, users will need to add react-test-renderer only.
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 its comprehensive mocking library
- In Jest, the developer can exercise complete control over 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 put the Enzyme into action, the developer will have to follow the installation instructions outlined in the Enzyme technical documentation.
For an 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 after that, Enzyme can be brought into the picture to build the tests for the application's UI. The result is a cleaner testing code that becomes easy to debug if the test breaks.
Experienced developers use them together as it makes React components testing easier, helps quickly detect bugs, and ensures that the User Interface of the application looks and acts as expected.
Split the Code
The code splitting method is used for segregating the codebase into a different bundle of components that are individually loaded on-demand or simultaneously. It is done to deliver 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 to 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 amazing, but as the app grows and evolves day-by-day, the bundle will also grow. While implementing third-party libraries in a bundle, it should be ensured that it doesn’t become too large because the larger the code size, the greater the time it will consume to load. Sidestep the large winded bundle, to get ahead of the loading problem, the developer will have to split down the large bundle. In code splitting, the independent domains are built for faster code loading and a better user experience of the application.
For this purpose, the bundlers have the feature known as Code-Splitting that can build multiple bundles and dynamically load them quickly at runtime.
Once the code has been segregated, the developer needs to decide how to use those segregated codes. 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 to load only the required components across the user interface. It improves the overall app performance because, in this case, only that component is loaded, which is needed for executing the required functionality demanded by the user. Meanwhile, there won’t be any need to reduce the code size of the app. Thus, the component which is not required is not loaded, and the initial loading time is reduced as such.
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 it’s not possible at run-time or on condition. To import the module, it is necessary to mention the path with a primitive string always.
Lazy Loading for React
React.lazy function enables to render a dynamic import just like a regular component. The code is split down into different components, and React.lazy loads only those components that have been requested without any help from the 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 the 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, then an optimum user-experience shall become difficult to achieve. Result? The bounce rate would increase, and the business opportunity would be lost. Not only this, but a slow-loading website can result in a bad ranking on the search engine result 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 the React potential to serve the users with a better experience.
Using CDN reduces the distance between the servers and the website visitors. It places the website content like text, images, videos, etc., on different servers worldwide and delivers such content 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. In the first option, the organizations can 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 like Cdnjs, JsDelivr, Google Hosted Libraries, Microsoft Ajax CDN, etc., can be utilized for calling the library. These CDN services have an extensive reach and are loaded with many libraries for use 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 simple and short transitions like toggling the states of the UI elements. While 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, navigation menu on the side, and the simplest way to show movement on-screen. In a declarative approach, the developers need to specify what things they want to make happen.
CSS declarative approach requires cheap interpretation. To show up the elements quickly 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 exact required design and is considered best for animations that require transformations.
For animations, the loading cost of a JavaScript library is relatively higher than the CSS. JavaScript consumes greater network bandwidth and high computation time.
JavaScript can provide better optimation 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 X and Y axes and take 500ms for the transition. The move class is implemented, and the transform value is changed to show transition on the screen. Separate classes are created to manage the animations.
CSS animations provide much more control over the animation duration, iterations, and iterations. It also helps in changing 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.
The animation itself is defined in CSS animations independent of the target element and implements the property called animation-name 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 of the keyframes.
CSS animations are amazing to use as they're supported by almost all popular browsers.
Activate gzip Compression
Gzip methodology is used for compressing the files of any type like plain text and images for rapid transfers and enhanced web performance. The lossless compression enables the webserver 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 the web page to load slower. Gzip reduces the web file size by 50-70% of the original file and boosts up 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 compression plugin bundle.js and configure gzip over the webserver to initiate it. Gzip can reduce a 7MB file to just 400kb to load the web page in just a few seconds.
Dynamic Gzip
The other method is to add a compression plugin to the application for compressing the bundle file dynamically before serving it. While compressing the files dynamically, the developer should be careful about the content.
There are various options to use 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 the record of file size and type.
Use Web Workers
When a web page is rendered, it has to operate 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 the website performance because, to get started, one process has to wait for the completion of the earlier process. That’s where the role of web workers comes into play by enabling the 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 known as 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 a huge number of tasks, then it would put an intensive load over 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 different threads execute in an isolated environment and use interprocess thread communication for interacting with the main thread. In this way, the main thread keeps pace with the rendering and manipulation of all tasks. Hence, it is recommended to put web workers into use during React development.
Save Time by Avoiding Inline Style
We use inline functions most of the time in the render method, but we often don’t know how it’s affecting the application’s performance. Every time the inline function is used by default, the render method is called, and a new function instance is created every time.
As we know that react uses virtual DOM to make real DOM updates, so when the 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 over the garbage collector, and 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 itself the event is bound to the function. As a result, every time, a new instance of the function would not be created when render is called. Thus, the processing is reduced, and performance is improved.
Wrapping Up
React JS development has become the need of 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 over the digital world. Implementing the aforesaid ten tips to improve the React game can further help to experience the wonders that this technology can provide. The top React JS development companies adopt these practices to provide better development services to help businesses achieve their perfection goals.
