Traceability in React


In web application that splits the html, javascript and css, the advantage during development is that we have traceability. Developers can view the source code and track the changes required in the files by looking where to make those changes. How can traceability be achieved in React JS?


In a React application, traceability is achieved through a slightly different paradigm, but it still very much exists.

In the traditional web application, where you split HTML, JavaScript, and CSS into separate files, the traceability you mentioned largely comes from the separation of concerns by technology. You know which file to look at based on whether you’re changing structure (HTML), behavior (JavaScript), or presentation (CSS).

In React, you instead have a component-based architecture, where each component is responsible for its own structure, behavior, and presentation. This might initially seem like it complicates traceability, because you can’t just go to the JavaScript file to change behavior. However, it actually can enhance traceability, because every piece of your app is contained within discrete, modular components.

For example, if you want to make changes to a specific part of your application, you don’t need to look through a large HTML file, a large JavaScript file, and a large CSS file to find the relevant code. Instead, you simply find the relevant component, and all of the code you need to change is right there.

Furthermore, React and modern JavaScript development tools often include features to aid in traceability:

  1. Developer Tools: Tools like the React DevTools extension for Chrome can be used to inspect a running React application, view the component hierarchy, see the props and state of each component, and so on.

  2. Source Maps: Source maps can be generated by your build process (for example, if you’re using Create React App or a custom Webpack setup). Source maps allow the browser to translate from the built JavaScript code back to the original source code, which means that when you’re debugging, you can see the original React and JSX code instead of the transpiled and minified JavaScript that’s actually being run.

  3. Error Boundaries: In React, you can use error boundaries to catch JavaScript errors anywhere in a component tree, log those errors, and display a fallback UI.

  4. PropTypes and TypeScript: PropTypes (or TypeScript, if you’re using it) add a level of type checking to your components, which can help prevent bugs and make it clear what data each component expects to receive.

So even though the way you achieve traceability in a React application is a bit different from a traditional web app, it’s still very much a core part of developing in React.

Browser Source to Component

So it is possible in React from viewing the source code in the browser and trace it back to the components?

Yes, with the use of source maps and the React Developer Tools extension, it’s possible to trace elements in a React application back to their original source code.

Source Maps provide a way of mapping code within a compressed file back to its original position in a source file. This can be very helpful for debugging code in production. It can help the developer to identify where in the original source code a particular piece of functionality is coming from.

React Developer Tools is a browser extension (for Chrome, Firefox, and others) that allows you to inspect a React component tree in the browser’s Developer Tools. You can inspect a component, see its props and state, and trace it back to the source file where the component is defined.

To use it, you simply inspect an element in your browser’s built-in developer tools, and it will highlight the corresponding component in the React Developer Tools.

By combining these tools, a developer can start with a visual element in the application, inspect it to identify the React component, and then use the source maps to find the exact location in the source code where that component is defined. This makes the process of tracing functionality from a running React application back to the source code quite manageable.

Is there other useful tools like Sapling for VS Code to quickly navigate a React JS codebase?

Yes, there are several tools and extensions that can help you navigate and work with a React JS codebase more efficiently in Visual Studio Code. Here are a few of them:

  1. ES7 React/Redux/GraphQL/React-Native snippets: This extension provides you with snippets in ES7 with Babel plugin features for JavaScript and React.

  2. Prettier - Code formatter: Prettier is an opinionated code formatter that supports JavaScript, TypeScript, and CSS. It helps ensure that your code follows a consistent style.

  3. VSCode React Refactor: This simple extension provides a way to refactor JSX components to their own file/module. It can come in handy when you have components that have grown too large or need to be reused elsewhere in your code.

  4. GitLens — Git supercharged: This is not React-specific, but it’s incredibly helpful in any codebase. It helps you to visualize code authorship at a glance via Git blame annotations and code lens, seamlessly navigate and explore Git repositories, and more.

  5. Path Intellisense: This extension autocompletes filenames in your code, helping you to quickly reference the correct file.

  6. Reactjs code snippets: This provides code snippets for React development in ES6 syntax.

  7. React Inspector: This provides a development inspector similar to the React Native inspector for web projects.

These tools can significantly improve your productivity and make it easier to navigate and understand a large React codebase.