Click-to-Component Source Code Analysis

Click-to-component is a React component that enables one-click navigation to source code, significantly improving development efficiency. Here I attempt to read the source code and document key points.

Source Code Structure

The project uses pnpm as the package management tool, with pnpm workspace managing multiple packages.

The core package is click-to-component-react under packages, while the apps directory contains projects that integrate this component package for testing and validation.

├── apps
│   ├── cra
│   ├── next
│   └── remix
├── package.json
├── packages
│   └── click-to-react-component
├── pnpm-lock.yaml
├── pnpm-workspace.yaml
└── turbo.json

Source Code Analysis

Starting from the index entry point for source code interpretation.

export const ClickToComponent =
  process.env.NODE_ENV === 'development' ? Component : () => null

Here, NODE_ENV is used to determine if it’s a development environment. If it is, the Component is returned; otherwise, a null component is returned. The benefit of this approach is that in production builds, this component won’t be included, reducing bundle size.

When the component loads, the window directly listens for click/contextmenu/keydown/keyup/mousemove/blur events. When clicked, the event can capture the target element.

In development mode, elements have properties starting with __reactInternalInstance$ or __reactFiber. These properties point to the fiber object.

The fiber object has a _debugOwner property, which points to the parent fiber object. Using the following logic, you can obtain nested fiber objects all the way up to the root fiber object.

  const instances = new Set()
  let instance = getReactInstanceForElement(element)

  while (instance) {
    instances.add(instance)

    instance = instance._debugOwner
  }

Additionally, the fiber object has a _debugSource property, which points to the source code file.

  const {
    columnNumber = 1,
    fileName,
    lineNumber = 1,
  } = instance._debugSource

Note: Production builds also have fiber properties on elements, but they lack debug property information

Once you know the source file path, line and column numbers, you just need to combine them with URL Scheme to navigate to the corresponding source file. VSCode has excellent URL Scheme support, refer to VSCode URL Scheme.

Final Thoughts

This completes the source code analysis of the entire component. The implementation logic isn’t complex but tests fundamental knowledge:

1. React Fiber
2. Tree shaking
3. Event listening
4. URL Scheme

The component demonstrates how React’s internal debugging information can be leveraged to create powerful developer tools that enhance the development experience without impacting production performance.