ReactJS has transformed web development, bringing fast, responsive, and dynamic applications that provide an engaging user experience. However, monitoring ReactJS applications poses unique challenges. Given that React apps rely on complex client-side interactions and dynamic page rendering, traditional monitoring approaches may fall short. This blog will dive into these challenges and explain how synthetic monitoring can be an effective solution.
Understanding ReactJS Monitoring Challenges
Monitoring traditional server-rendered websites has typically been straightforward. The server responds to HTTP requests with complete HTML documents, making it easy to track metrics like page load time and server performance. But with ReactJS, much of the content is rendered on the client-side. This brings specific monitoring challenges:
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Client-Side Rendering: ReactJS apps render content dynamically in the browser, making it harder to track load times for individual elements and user interactions compared to traditional server-rendered sites.
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Single-Page Application (SPA) Complexity: ReactJS often powers single-page applications, where interactions update only portions of the page instead of loading a new one. This makes it difficult to monitor page transitions, track user flows, or understand which elements are slowing down the application.
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Third-Party Dependencies: React applications often rely on third-party libraries and APIs to provide features, which adds complexity when monitoring. A delay in these dependencies can impact app performance, but tracking it can be challenging without proper tools.
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User Interactions and Events: React apps are highly interactive, often with dozens of clickable elements and transitions per page. Monitoring these specific interactions and their impacts on performance is essential to understanding and optimizing user experience.
To address these challenges, companies need a monitoring strategy tailored to the specific nature of ReactJS applications.
Monitoring Component Mounts with Profiler
The number of times components re-render, along with the amount of resources and time taken, can say lot about the performance of your React application in production. The Profiler component is a built-in React component that measures “mount” or “update” time of a component subtree. whenever a component is updated or mounted, Profiler’s onRender function is time stamped. Profiler provides an approachable way to view problems in React apps.
import { unstable_Profiler as Profiler } from "react"
<Profiler id="Counter" onRender={callback}>
<Counter />
</Profiler>
The id prop identifies the reporting, while the onRender function is associated with arguments when the Counter component is mounted or revised.
function callback(id, phase, actualTime, baseTime, startTime, commitTime) {
log("id: " + id, "phase:" + phase, "actualTime:" + actualTime, "baseTime: " + baseTime, "startTime: " + startTime, "commitTime: " + commitTime)
}
The function’s arguments are collected time stamps of when the Counter component was rendered. We will take a look at each of the parameters.
id. The unique ID associated with Profiler component.
phase. This detects the phase whether in “mount” phase or “update” phase.
actualTime. The time taken by Profiler to render committed updates.
baseTime. The time taken by one of the components in the Profiler tree to mount or update.
startTime. Logs the time stamp Profiler begins measuring the mount/render time for its descendants.
commitTime. The time React took to commit an update.
Monitoring Components that are Re-rendered Using React Developer Tools
During development, if you learn which component is being re-rendered, it can save your application in production from various performance bottlenecks. React Developer Tools make that simple for developer by coloring the component boundaries, whenever they are re-rendering. If your main components re-render, the edges that capture the Counter and Count components will be briefly highlighted.
The type of color that appears depends on how often/frequent a component is re-rendered, giving you the ability to easily identify which component updates the most frequently so you can optimize it appropriately.
| green – low frequency update
| blue – average frequency update
v red – denotes a very frequent update
Identifying Perf Issues with React.addons.Perf
To start Perf, you must call Perf.start() from the console, record the action, and call Perf.stop() to stop Perf. Then, you can call any of the following methods to view sets of useful measurements.
Perf.printWasted()
Perf.printWasted() is the most useful method you call on React.addons.Perf. Perf.printWasted()tells you amount of time lost contracting render tree and comparing virtual DOMs with each other. These components are mentioned above are prime candidates to improve the performance of your React application.
Perf.printInclusive() / Perf.printExclusive()
Perf.printInclusive() and Perf.printExclusive() return amount of time it appropriated to render your components. Most developers won’t find this method very useful, as the performance issues triggered by rendering are normally solved by not rendering using the above method: Perf.printWasted().
However, the method can help you identify components that are performing heavy computations in lifecycle methods. You will learn that after fixing printWasted issues, it is your un-optimized application code that is hogging those precious resources. Alternatively, you can bring the standard Chrome DevTool’s JavaScript Profiler and take a look at the most heavy function calls directly.
Perf.printDOM()
Perf.printDOM() shows all DOM operations triggered during the rendering of React trees. If you been playing with ReactJS for quite some time, then you know this is perhaps the most cumbersome part. To browse an endless list of rows and column if your app is pretty complex, can take eternity to detect what exactly went wrong.
Once your first set of components are rendered, you expect that future re-renders would reuse existing DOM nodes and not create fresh nodes–an optimization afforded by React’s virtual DOM and taken granted by every React developer.
Perf.printDOM() comes handy to find peculiar, expensive browser oddities or monitor major, unpredictable DOM modifications.
Synthetic Monitoring for ReactJS Web Applications
Synthetic monitoring is a proactive approach that involves simulating user actions to test application performance in real-time, without waiting for actual user interactions. Synthetic monitoring shines in environments like ReactJS applications, where user interactions drive much of the experience. Here’s how synthetic monitoring can address key challenges in ReactJS:
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Simulating User Paths: Synthetic monitoring simulates user paths and interactions, allowing you to test specific scenarios in the React app to ensure they work smoothly. This is especially valuable for React-based SPAs, where each user interaction dynamically updates parts of the page.
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Tracking Component Load Times: By simulating actions and tracking load times, synthetic monitoring can provide insights into specific React components that are lagging, helping you target your optimization efforts effectively.
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Monitoring Third-Party Integrations: Synthetic tests can help you monitor third-party services in real-time, so you know if a dependency, like a map API or payment gateway, is affecting user experience.
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Consistent Monitoring Across Locations: Synthetic monitoring enables you to run tests from different geographic locations, ensuring that React apps perform well for users worldwide. This can help you detect any latency that may arise from content delivery networks or server locations.
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Early Detection of Issues: Synthetic monitoring is scheduled, so it continuously runs checks, enabling you to identify potential performance issues early before users experience them.
Using Dotcom-Monitor for Synthetic Monitoring
Dotcom-Monitor offers a powerful synthetic monitoring solution specifically designed for complex, client-side applications like those built with ReactJS. With Dotcom-Monitor, you can:
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Simulate User Journeys: Dotcom-Monitor enables you to create scripts that simulate user journeys, making it easy to test critical paths in your React app, like registration, checkout, or any other vital user interactions.
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Comprehensive Component Analysis: Track how long individual components take to load and identify those that need optimization. With Dotcom-Monitor, you get detailed performance insights, helping you focus on specific elements that impact user experience.
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Global Coverage: Test your ReactJS application from various locations worldwide to ensure consistent performance for all users, regardless of where they’re accessing your site.
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Detailed Reporting and Alerts: Receive real-time alerts when something goes wrong and use Dotcom-Monitor’s comprehensive reports to analyze trends, bottlenecks, and response times.
With Dotcom-Monitor, ReactJS developers gain a robust monitoring tool that brings clarity to complex applications, ensuring that their apps run smoothly and users stay engaged.
Monitoring ReactJS Applications: Conclusion
ReactJS applications offer a fantastic user experience but bring unique monitoring challenges. Traditional monitoring methods may overlook client-side interactions and third-party dependencies, which are critical to understanding true app performance. Synthetic monitoring provides a proactive, reliable way to track and improve the performance of React apps, ensuring they meet user expectations and business needs.
By using synthetic monitoring solutions like Dotcom-Monitor, you can confidently address the complexities of React applications and create a smooth, reliable experience for all users. Whether you’re looking to improve component load times, monitor third-party integrations, or ensure performance across regions, synthetic monitoring offers an effective way to keep your React app performing at its best.
