React Devtools: Complete Guide For Modern Web Developers
Creating a modern React application can be intimidating- it’s like building a skyscraper. The finished product can be beautiful, but if a square-foot section of the foundation is weak, you have a big problem. Just like a skyscraper, developers have weak points - those points are bugs.
The way the average developer finds bugs today is like trying to find a wire that is faulty by randomly drilling holes into the drywall of a skyscraper. Not very helpful or efficient. This is why we need React Developer Tools; we need the architectural blueprint to the applications construction, so we can inspect, debug, and optimize our work.
That said, the official React Developer Tools are only part of the modern React ecosystem, which is more like a bustling metropolis filled with assorted libraries, extensions, and IDEs to help proactively give a developer more time and confidence in their work. In this guide, we will cover only the essentials, from the official React Developer Tools to testing and lastly IDEs. In the end, you will have everything you need for all the React component construction. Furthermore, a developer who is hunting for bugs will be transformed into architect who builds with purpose.
Tools like Keploy’s automated testing platform can complement React DevTools by helping developers quickly detect and resolve bugs before they hit production.
What Are React Developer Tools?
At the heart of it, React Developer Tools is a Chrome and Firefox browser extension that can be used to inspect your React component tree. To help clarify the significance of this, you will need to be educated about the Virtual DOM. When React is rendering your components, it doesn’t actually manipulate the webpage’s HTML (the DOM) directly. React creates a duplicate copy in memory called the Virtual DOM. When the state of your app changes, React will update the virtual copy, compare it to the previous version, and will efficiently update only the parts of the real HTML DOM that you changed.
How to Install and Use React Developer Tools
Getting started is as easy as pumping your brakes. This section will answer the most common question “How do I install and use React Developer Tools?” and will have you set up in just a couple of minutes.
Installing from the Chrome Web Store
The easiest way to get the extension is from the official web store.
- Navigate to the React Developer Tools - Chrome Web Store page.
- Click Add to Chrome.
- A popup will ask for permission - click the Add extension button in the popup.
- Once installed, its atom-like icon will appear in your browser’s toolbar. This icon is a status indicator:
- Colored Icon: You’re on a site using a development build of React. The tools are active.
- Grayscale/Disabled Icon: You’re on a site that either doesn’t use React or is using a production build.
Opening and Using DevTools
You can access the tools by pressing F12 (or Cmd+Option+I on Mac). You’ll see two new tabs: Components and Profiler. The extension can be used in two different modes:
- Embedded Mode: their default viewing option; this view shows the tools docked in the main developer panel of your browser, and is fine for established debugging, the tools in the DevTools panel.
- Floating Mode: by clicking on the gear icon in the DevTools panel you can pop the tools out as a standalone window; very useful if you have a bigger monitor and want to see atoms and their DevTools side-by-side without too much cramping.
Key Features: How React Developer Tools Help in Debugging
So, what are the key features of React Developer Tools? At their most abstract level React Developer Tools have tendencies to interject, debug, and profiling, and they are effectively managing your application behavior.
The Components Tab: Inspecting Component Instances
The Components Tab serves as your primary debugging tool. It provides a visual representation of your entire component tree. Let’s work through a real-world use-case:
Let’s say UserProfile component is not showing the user’s name as expected.
- Locate the Component: UUsing the inspector tool (the crosshairs icon) in the Components Tab, click on the user profile area of your app. The DevTools will immediately highlight your UserProfile component in the component tree.
- Inspect its Data: With UserProfile selected, the right-hand panel shows its props, state, and hooks. You might see a prop called userName with a value of undefined.
- Debug in Real-Time: This powerful tool allows you double-click on that undefined value and type in a test name such as "Alice". If you see the name appearing as expected on the UI, that means the component is functioning correctly but is receiving the wrong data. The issue is with the parent component sending the prop, not with UserProfile.
The ability to inspect component instances and change their data quickly in real-time is why the tool is so powerful. In complex, large applications, you can easily find components by name using its filter bar.
The Profiler Tab: Analyzing Performance
The Profiler tab is your best friend when tackling a slow or laggy application. You hit record, interact with your app, and hit stop recording to see a summary of the performance. It summarizes the performance in two useful formats:
- Flamegraph Chart: This will display the rendering work for the whole application you recorded. Wider bars indicate components that took longer to render, so those pieces will be your best bets for optimizing.
- Ranked Chart: This will give you a simple list of your components, ordered by performance with the slowest at the top. If the flamegraph seems a little daunting, this should give you a good, simple place to start to figure out what’s going on.
The React Hooks Profiler
One thing you can do with the Profiler is set it to “Record why each component rendered”. This effectively makes it a React Hooks Profiler and is a great tool to help debug tricky issues with hooks, such as useEffect firing too many times because you didn’t set the dependency array correctly, or useMemo not might not be memoizing as expected.
A List of Essential React Developer Tools and Libraries
The official DevTools are great, but they are best utilized as part of a bigger toolbox. Here is a list of React developer tools and libraries that help tackle other parts of the development lifecycle.
State Management: Redux and Redux DevTools
As your React app goes from a small village to a big city, it becomes a challenge to manage data. In a small app, it’s easy to pass data down to child components with props, but when a child component that is several levels deep along a tree needs data from a component up high in the tree, you are forced to pass that data through every single child along the way, even child components that do not need the data themselves. What results from this scenario is a tedious and error-prone method known as “prop drilling.”
The core concepts of Redux are:
- Store: The single object that holds all your application’s state.
- Actions: Plain JavaScript objects that describe an event that has happened (e.g., { type: ‘ADD_TO_CART’, payload: 'product-123’ }). They are the only way to send data to the store.
- Reducers: Pure functions that receive the current state and an action, and returns a return value of the new state. It tells Redux how the state of the application will change when responding to actions
Build Tools: Vite
A fast development server is essential to stay in that productive flow state. Each time you save a file, you want to see the change in your browser immediately! This involves using a build tool.
Generally speaking, traditional bundlers (like Webpack, in its earliest stages) are like factories. First, a factory must produce a car in order to show you a car. When you start your development server, the bundler crawls through your entire app, creates a complete dependency graph of all the files you have imported, and then it will actually bundle everything you have done into a single JavaScript file.
Vite employs a game-changing technique. It is akin to a modern car factory applying just-in-time manufacturing. Vite does not create everything up front; Vite takes advantage of native browser support for ES Modules (ESM). This means when you invoke the dev server, it does almost nothing. It serves your files on demand just as the browser requests them. When you request your App.js, it serves App.jsfile. When App.js imports a button component, the browser then requests the button file. On-demand means that Vite is able to start a server for you nearly instantaneously.
Testing Frameworks: Jest and React Testing Library
Automated testing refers to the practice of writing code to ensure your application code works correctly. It serves as the safety net that enables you to add new features or perform refactoring on existing code with the confidence that you did not break anything.
In the React ecosystem, the winning combination is Jest and React Testing Library (RTL). It is helpful to think about their different roles:
- Jest is the laboratory. It is the entire testing environment for you. It is the “test runner” that discovers your test files, executes the code within those files, then reports back to you whether they passed or failed. It also provides a way to make assertions e.g., expect(sum(1, 1)).toBe(2)) and a way to create “mocks” to isolate your code from external dependencies.
- React Testing Library is the scientific method. It is a suite of tools and best practices for testing React components specifically. RTL’s central philosophy is that you should test your components from the user’s perspective. Rather than testing a component’s internal state or props (which are purely implementation detail and can change), RTL will encourage you to write tests that sort of mimic how a user would interact with the UI.
The Keploy Advantage for Testing
As we all know, a React front end is connected to backend APIs, and it can be as reliable as these APIs are reliable. Very often, front end development can get completely stalled or slowed down when the backend environment is unstable, incomplete, or not even available. Manually recreating tests against these APIs can be hard or impossible, and even using something like Postman creates tons of ongoing work for you to setup, test, and maintain.
Keploy is an open source tool that literally changes this process. Keploy works by “recording” the real API traffic between your front and back end while you are working normally in development or manual tests with your front end (either good or bad). From that recorded traffic, Keploy automatically generates:
- Test Cases: It creates fully functional backend tests that verify your API’s behavior.
- Data Mocks: It creates realistic, stateful mock APIs. These are “stubs” of your backend that your frontend can talk to, even when the real backend is down.
Which means you can keep building your React application without any backend dependencies. You also get full functional regression tests against the business logic aspect of your APIs without writing any test code yourself. You dramatically speed up the development cycle, and your front end gets full testing coverage along with your backend APIs being in perfect sync and in tightly defined slippage.
What is the Best IDE for React?
Your IDE or code editor is where you’ll spend most of your time as a developer. It’s often simply a matter of personal opinion as to what is the best IDE for React, but below are the mostly popular choices which each have their own strengths.
Conclusion
React Developer Tools are necessary starting point for being able to build and debugging React applications. Using the React developer tools, you should be able to inspect and debug component tree and profile render performance of your components. Mastering the Developer tools is your first significant step.
However, we achieve real mastery via the larger ecosystem. By combining DevTools with state managers like Redux, build tools like Vite, testing frameworks like Jest, and IDEs like VS Code, we have an efficient, scalable, and high-quality development workflow. We moved from writing code to architecting high-quality, maintainable software.
Frequently Asked Questions (FAQ)
Q1: Can I use React Developer Tools with React Native?
A: Yes! but not as a browser extension. You will use a standalone version of the DevTools for React Native. You can install it globally using your terminal (npm install -g react-devtools) run it using the command react-devtools command. This version will attach to your running React Native app and offers a very similar inspection and debugging experience.
Q2: Why can’t I see the “Components” and “Profiler” tabs in my browser?
A: This is a common issue with a few possible causes:
- Your website was not built with React.
- Your website is using a production build of React that stripped the DevTools hooks.
- You need to close the developer panel and reopen it.
- Try restarting the browser or in your browser settings ensure the extension is enabled.
Q3: Should I learn Redux or the built-in Context API first?
A: It’s very much recommended to learn React’s built-in Context API first. Context is great when you want to manage state that has to be accessed by multiple components at different levels like theme data or status on logged-in user. Move to a more powerful library like Redux only if your state logic has become so complex Context has become too unwieldy to manage.
Q4: Do I need to learn all these tools to be a good React developer?
A: Absolutely not. There is so much going on in the React developer tools space right now, just focus on mastering the foundational React developer tools first. Then as you run into the specific problems that each of the tools is claimed to solve, adopt the new tools accordingly. Do not feel pressured to learn everything at once. A good developer knows which tool to grab when the time is right.
Q5: Are React Developer Tools free?
A: Yes, the official React Developer Tools browser extension and standalone application are 100% free, and are open-source and maintained by the React team at Meta.
