React performance monitoring

Monitoring performance in single-page React applications is difficult. Unlike multipage server-rendered apps, where we can rely on straightforward metrics like load time, there are many different ways that issues in React apps can degrade UX.

In this article, we’ll discuss four significant sources of performance issues in React applications and how to mitigate them.

Tackling slow JavaScript code

Performance optimization starts with frontend code. React code containing extra loops, memory leaks, or unnecessary layout refreshes can slow down your application and lead to a laggy user experience. To prevent and catch slow JavaScript code, consider the following approaches:

• Use the Chrome Profiler during development to identify bottlenecks and optimize your JavaScript code. Adding the React Developer Tools extension allows you to specifically profile React components and eliminate costly re-renders
• Use a synthetic monitoring tool like Rigor before deploying to production. These tools simulate user behavior to help you analyze performance under controlled conditions and identify problem areas to optimize, such as slow-loading JavaScript files. However, note that these tools can’t perfectly replicate the wide range of real usage conditions
• Monitor your React app in production with real user monitoring (RUM) tools like LogRocket. RUM tools provide insights into how everyday users experience and behave on websites and applications. This can help you spot patterns and problems that may only happen to particular users, on certain browsers, or under specific conditions

Leveraging these tools can help you quickly diagnose and resolve problems with slow JavaScript code, ensuring a smooth and responsive user experience.

Preventing frontend errors

Nothing is more disruptive to a user than experiencing an error while trying to get something done in your app. Consider implementing the following React performance monitoring strategies to catch or prevent frontend errors:

• Unit testing tools like Mocha or Jest can help you test individual components and functions, ensuring they work as expected and minimizing potential errors
• End-to-end testing frameworks like Puppeteer and Cypress can simulate user behavior and validate the entire user journey
• Error monitoring tools like LogRocket provide real-time error tracking so you can quickly pinpoint and resolve problems in your deployed apps. With LogRocket, you can leverage error tracking features alongside real user monitoring and other capabilities to better understand issues at their root, scope their impact, and quickly ship a fix

Get visibility into what is and isn’t working for your users to help ensure they can use your React application and all its components at any time without issues or confusion.

Optimizing load times

For ecommerce sites or consumer apps, load time can be even more critical than in-app performance. Slow load times can lead to high bounce rates and poor UX. To address this issue:

• Use Chrome Lighthouse to audit your app's performance, accessibility, and best practices. Lighthouse provides actionable insights to improve your app's load time and overall performance
• Utilize tools like SpeedCurve to measure and analyze your app's load time under various conditions, helping you optimize your app for better performance
• Implement RUM tools like LogRocket to monitor your app's performance in real-time, capturing valuable insights to improve load times and user experience

Monitoring load times in your React application can help you identify elements or resources that slow down page load speed so you can optimize accordingly.

Addressing slow API calls

Your JavaScript code’s performance doesn’t matter if you’re making calls to slow backend APIs. To address this issue:

• Use application performance monitoring (APM) tools like Datadog to monitor your own APIs, identifying bottlenecks and optimizing performance
• Use RUM tools to detect where API calls may be slowing down the frontend. This is especially crucial if your app relies on third-party APIs, which can be challenging to monitor otherwise

These tools can help you monitor API response times, error rates, and more to better understand how backend performance impacts UX and get an overall picture of application health.

How LogRocket helps with React performance monitoring

It’s easy for React performance monitoring to become an overwhelming and time-consuming process.

Some tools are helpful for performance monitoring in development environments, but not for monitoring performance in production. Others may inundate teams with noisy alerting, unclear user feedback, excessive data to sort through, and more, with no insight into the root causes of issues or their impact on end users.

LogRocket makes it easy to see exactly how real users experience your React apps, as well as the “why” behind any issues:

• Monitor errors and discover novel issues with real-time alerts and essential data to help you reproduce, diagnose, scope, and resolve problems efficiently
• Dig deep into the root cause of errors with natively integrated session replay that provides the technical telemetry and context you need to understand what’s going on and why
• Visualize essential analytics with familiar structures like charts, dashboards, conversion funnels, heatmaps, and more to quickly identify trends and anomalies
• Collaborate across teams more effectively with one source of truth that stakeholders can use to get the information they need and share it within the same platform
• Find issues faster with error triaging, automatic severity scores, and machine learning models that automatically surface the most impactful problems affecting your users

Quickly identify, understand, and resolve problems with your React apps at their source. Get a complete picture of what’s happening so you can easily route alerts and errors to the right person and ensure the ideal digital experience for every user.

Try LogRocket for free today!

Be confident that the issues and opportunities you address will enhance the user experience in your React app and have a meaningful impact on the KPIs that drive your business.

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