Chasing the Missing ’n’: A Debugger’s Odyssey

How a Missing ’n’ Led Me to Discover Circular Dependencies

This week has been intense for me — I was stressed beyond my limits, and oh well, it’s only Wednesday. I could really use a weekend squeezed in between today and Thursday. Just superficial wishes, though.

So, there I was, on my way to school, when I got a text from work saying some actions had stopped working. Naturally, I paused my prep for school to check it out. Turns out, it was broken in production but worked perfectly fine in the dev environment. Yep, welcome to the hell loop of debugging!

The error message simply said, “A server error occurred. Further information is available in the digest.” Super helpful, right? I checked the Vercel logs and saw the bug, but I couldn’t make sense of it. What does ReferenceError: Cannot access ’n’ before initialization even mean? I didn’t even have a function or variable named n.

The logs pointed to my auth action as the culprit, but I couldn’t fathom how. I couldn’t even recreate the error locally at first. After some head-scratching, I ran a build version, and voilà — the error showed up locally! Progress!

I updated the next-safe-action package, thinking the bug might be there, but nope. It didn’t work. Though, funnily enough, my mysterious n was replaced with c. I guess that’s one step closer to an A — because c is at least on the academic grading scale! 😅

To speed things up, I hopped on a call with my colleague. The update didn’t fix the main issue, but it did resolve a type inference problem with my schema. A small victory, I suppose. yay 🎉

While researching, I stumbled across the term circular dependency. Honestly, the definition made my brain feel like it was running in circles. I had no clue what it meant at first. After two days of trial, error, and frustration, I finally pieced it together thanks to this handy package: circular-dependency-plugin. It’s quite old but still does the job like a pro.

Also, big shoutout to BaseDash’s article for breaking down the “Cannot access ’n’ before initialization” error in a way that made perfect sense. That explanation was exactly what I needed to understand how JavaScript hoisting and initialization played a role in this mess.

And let’s not forget the Webpack GitHub issue discussion, which ultimately pointed me to the right tools to debug the problem. Community-shared knowledge is such a lifesaver — I mean, n might not exist in academic grades, but it sure schooled me in debugging!

Setting up the circular dependency plugin in my Next.js config repo was quick. I just installed it, followed the setup guide, and ran pnpm build. Magic! ✨ The plugin identified all my circular dependencies. Seeing the issue visually made everything click—it really was a circle.

What are circular dependencies?

Imagine two coworkers, Alice and Bob, who both depend on each other to get work done:

• Module A requires Module B, and Module B requires Module A.
• The loop can extend further: Module A depends on Module B, which depends on Module C, which depends back on Module A.

Why are circular dependencies a problem?

1. Unpredictable Behavior: Circular dependencies can cause weird and hard-to-debug errors, like ReferenceError: Cannot access ’n’ before initialization.
2. Performance Issues: Resolving circular dependencies can slow down the app or even cause infinite loops.
3. Build Failures: Tools like Webpack or Node.js might fail to compile or run your application.
4. Code Maintenance Headaches: Circular dependencies create tightly coupled code, making it harder to refactor or test.

How do you detect circular dependencies?

You can detect them manually by reviewing your imports, but tools like the circular-dependency-plugin make it faster and more reliable. This plugin visualizes dependency loops, so you can spot and fix them easily.

How do you fix circular dependencies?

1. Refactor Your Code: Break the dependency loop by rethinking how your modules are structured.
2. Introduce an Intermediate Module: Use a third module to share common functionality instead of having two modules depend on each other directly.
3. Use Dependency Injection: Pass dependencies into modules as parameters instead of requiring them directly.

My key takeaways:

1. Rest Matters: This week was exhausting — early classes, work, assignments — it all piled up. Learn to take breaks. You can’t pour from an empty cup!
2. Don’t Dry Out: When you’re stuck, don’t hesitate to lean on your colony. Talk to teammates or mentors. Collaboration saves time and sanity.
3. Learn Along the Way: Even if it’s frustrating, every debugging session teaches you something new.