As developers, we're constantly looking for tools that streamline our workflow, reduce cognitive overhead, and improve the overall developer experience (DX). Over the years, we've seen a host of dev tools revolutionize how we write, debug, and refactor code—Prettier for formatting, ESLint for linting, Vite for blazing-fast development servers, and so on.

But even with all these advancements, there’s one persistent pain point, especially in large-scale component-based applications:

"Where the heck is this component defined?"

Whether you're working on a Next.js app with hundreds of React components or a monorepo managed by multiple teams, tracing UI elements back to their source code can be a frustrating time-sink.

Enter LocatorJS — a devtool that addresses this exact problem with simplicity and elegance.

What is LocatorJS?

LocatorJS is an open-source developer tool that helps you locate the source code of React, Vue, SolidJS, or Qwik components directly from the browser UI.

Imagine inspecting a button on your app and with a single ⌘+click (or Ctrl+click on Windows), your code editor instantly opens the file and line where that button component is defined.

That’s the magic of LocatorJS.

It bridges the gap between your browser’s UI and your editor’s file system. No more guessing, Ctrl+F, or hunting through nested folders.

Why Should You Use LocatorJS?

If you’ve ever found yourself asking:

“Where’s this component defined?”
“Which file contains this button?”
“What’s the actual source of this modal?”

…then LocatorJS is a no-brainer.

Here’s what it brings to the table:

Pros of LocatorJS

Massive DX Boost
Editor Integration
Minimal Setup
Multi-Framework Support
Configurable & Lightweight

Cons of LocatorJS

No tool is perfect. While LocatorJS offers great productivity, it's good to understand its limitations.

Requires Editor Integration
Not Yet Mainstream
Doesn’t Support All Frameworks
Slight Overhead in Production

How LocatorJS Works (Behind the Scenes)

LocatorJS adds metadata to DOM elements during the build or dev process. This metadata includes:

File path
Line number
Component name

It injects this metadata as a special HTML attribute, e.g., data-locatorjs-id, that can be picked up by the LocatorJS browser extension or browser script. When you click an element, it reads the attribute and opens the relevant file in your editor.

Under the hood, it uses source maps and Babel/AST parsing to trace back the rendered elements to their origin in the source code.

🛠️ How to Use LocatorJS in Your Project

Let’s go step-by-step on getting LocatorJS up and running in a React or Next.js project.

1. Install the Plugin

npm install --save-dev @locator/runtime

For Vite or Next.js, you’ll also need the respective plugin.

2. Add LocatorJS Plugin

For Next.js:

Use the @locator/next plugin:

npm install --save-dev @locator/next

Add this to pages/_app.jsx or app/layout.jsx (or any other global file):

import setupLocatorUI from "@locator/runtime";if (process.env.NODE_ENV === "development") {setupLocatorUI();}

3. Install the Browser Extension

Grab the official LocatorJS browser extension for:

Chrome: Link
Firefox: Link

This extension reads the DOM metadata and lets you click on any component in the browser and open it in your code editor.

4. Use It!

Run your app in dev mode.
Open the browser with LocatorJS enabled.
Hover over UI components — you’ll see component names in a tooltip.
Alt + Click on the component — it opens in your editor at the exact location.

Optional: Use Without Extension (Manual Script)

If you prefer not to use the browser extension, you can inject the LocatorJS script manually:

<script src="https://unpkg.com/@locator/runtime/dist/locator-runtime.umd.js"></script><script>window.**LOCATOR_CONFIG** = {editor: "vscode",projectRoot: "https://www.syedalinaqihasni.com/Users/yourname/yourproject",};</script>

This makes it possible to use LocatorJS in internal tools, previews, or demos.

Example Use Cases

1. Large Component Libraries

If you're working on a design system or component library with dozens of shared UI elements, LocatorJS helps pinpoint exact file locations quickly.

2. Agency or Freelance Projects

Jumping into a legacy client project? LocatorJS can drastically reduce orientation time.

3. Team Collaboration

Reviewing a PR and wondering where a component came from? Open the running app, click, and jump to the source.

Advanced Configuration

You can customize how LocatorJS works via environment variables and options:

locatorPlugin({rootDir: './src',editor: 'vscode',useRuntime: true,// Adds tooltip and hover info});

You can also integrate with JetBrains editors (like WebStorm) using custom URL schemes or open-file plugins.

Security & Production Considerations

LocatorJS is safe to use in dev environments, but in production:

Remove metadata attributes before deployment.
Disable runtime scripts to avoid exposing file paths to users.

Most plugins automatically strip LocatorJS metadata during production builds unless explicitly configured to do otherwise.

Final Thoughts: Why I’m Betting on LocatorJS

I’ve personally added LocatorJS to few of my React/Next.js freelance and personal projects. The time it saves when jumping between UI and code cannot be overstated.

It's one of those tools that once you try, you wonder how you lived without it—like Prettier, but for navigation.

If you’re working on complex UIs, collaborating across teams, or onboarding new devs regularly, I highly recommend giving it a spin.

Useful Links

Website: https://www.locator.dev/
GitHub: https://github.com/infi-pc/locatorjs
Developer: https://x.com/_michaelmusil
Support: https://x.com/locatorjs

Let’s Discuss

Have you tried LocatorJS?
Planning to integrate it in your stack?
Got tips, tricks, or questions?

Drop a comment below or DM me — always happy to geek out about devtools that make life easier.

Want more developer-first content like this? Follow me here on LinkedIn and check out syedalinaqihasni.com/blogs for blogs, code tips, and freelance resources.

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