React is an efficient JavaScript front end library and has become one of the most popular JavaScript libraries today. React helps you to curate applications more easily and helps make them more scalable and robust. React is in demand by most organizations and there is a huge demand for React developers and experts. If you haven’t started working with React yet, it would be beneficial to get some React Js training. To this end, you can enrol in a React Js course online.
React does a clever job on its own in terms of application performance, but when using complex applications, you may find issues with certain components. The following eight tips will help you to boost your apps performance.
1. Measure Render Times
Before you begin optimising, measure the time taken to render your apps key components. You can’t start improving without having a baseline. The recommended tool for this is to use the browser’s User Timing API.
2. Use The Production Build
React’s production build improves you apps performance in two ways. The first is that the file size of the production build is significantly smaller, which means that the page loads faster as the browser has to download, parse, and execute fewer elements. The second is that there is much lesser code in React production build as things like the profiling information and warnings have been removed. In production mode, mounting and update times have been shown to be consistently lower.
3. Function/Stateless Components and React.PureComponent
Two different ways of optimizing React apps at the component level are function components and PureComponent. Functional components reduce the bundle size as they are better at minifying than classes and they prevent construction of class instances. PureComponent on the other hand is good for optimizing UI updates.
4. Multiple Chunk Files
All applications start out nimble with just a few components. Once you start adding dependencies and features, it’s easy to end up with a large production file without realizing it. You can mitigate this by taking advantage of the CommonsChunkPlugin for webpack which helps you to separate your vendor, or third-party library code from your own application code. You’ll basically end up splitting the file into two bundles, namely vendor.bundle.js and app.bundle.js. Another advantage of this is that your browser doesn’t need to cache as often and parallel downloads the required resources which in turn reduces load times.
5. Dependency Optimization
When you start working on optimizing the size of your bundle, check to see how much code you are actually using for your dependencies. For example, if you’re using only a few of the 100 plus methods of lodash, you can use the lodash-webpack-plugin to remove the unused functions and reduce the bundle size.
6. Avoid Inline Function Definition in The Render Function
Inline functions will fail the prop diff whenever React does a diff check because in JavaScript, functions are objects. Using an arrow function instead will create a new instance of the function with each render. It is better to define the arrow function instead of defining the inline function for props.
7. Throttling and Debouncing Event Action in JavaScript
An event trigger rate is defined as the number of times an event handler is invoked in a specified period. Generally scrolling has higher trigger rates than mouse clicks. Very high trigger rates can crash your app. There are two methods to control this:
- Throttling is basically delaying the execution of some functions by a few milliseconds when an event is triggered. Throttling can be done by either executing the delay eventhandler or by controlling the number of events being triggered.
- Debouncing, on the other hand, is a technique used to prevent an event being triggered frequently. For example you can use the lodash’s debounce function to wrap the function you want to call.
8. Memoize React Components
Applications can be made faster by using an optimizing technique, memoization. Memoization stores the results of resource hungry function calls and returns the same cache result when the same input is given again. Given the same input, it is faster because it uses the same result instead of executing the function logic again.
In Summary
React applications can be optimized in many ways, some of which have been detailed above. But, bear in mind that it is important to have an understanding of how React components work, understanding diffing algorithms, and how rendering works in React. To learn more about React Js, consider enrolling in a React Js under web development courses online or offline.
Before you start optimizing, measure and benchmark your apps’ performance first. A tool like Chrome Timeline is handy to visualize and profile your components as this lets you see which components have been unmounted, mounted, updated, and the time they take relative to each other. This is a good first step towards optimizing your React App.
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