Code Smell 09 - What Should You Do With Dead Code?

Code that is no longer used or needed.

TL;DR: Do not keep code "just in case I need it".

Problems 😔

Maintainability
Extra reading
Broken intent
Wasted effort

Solutions 😃

Remove the code
KISS
Shrink codebase
Test behavior only
Trust version control

Refactorings ⚙️

https://hackernoon.com/refactoring-021-remove-dead-code

Examples 📚

Gold plating code or Yagni code.

Context 💬

Dead code appears when you change requirements, and you fear deleting things.

You comment logic, keep old branches, or preserve unused methods just in case.

When you do that, you lie about what the system can actually do.

The code promises behavior that never happens.

Sample Code 📖

Wrong 🚫

class Robot {   
  walk() {
    // ...
    }
  serialize() {
    // ..
  }
  persistOnDatabase(database) {
    // ..
  }
}

Right 👉

class Robot {   
  walk() {
    // ...
    }  
}

Detection 🔍

Coverage tools can find dead code (uncovered) if you have a great suite of tests.

Exceptions 🛑

Avoid metaprogramming. When used, it is very difficult to find references to the code.

https://hackernoon.com/laziness-chapter-i-meta-programming-6s4l300e

Tags 🏷️

YAGNI

Level 🔋

[x] Beginner

Why the Bijection Is Important 🗺️

Your program must mirror the MAPPER with a clear bijection.

Dead code breaks that mapping. The domain has no such behavior, yet the code claims it exists.

When you do that, you destroy trust.

Readers cannot know what matters and what does not.

AI Generation 🤖

AI generators often create dead code.

They add defensive branches, legacy helpers, and unused abstractions to make it look complete.

When you do not review the result, the smell stays.

AI Detection 🧲

AI tools can remove this smell with simple instructions.

You can ask them to delete unreachable code and align logic with tests.

They work well when you already have coverage.

Try Them! 🛠

Remember: AI Assistants make lots of mistakes

Suggested Prompt: correct=remove dead code

Without Proper Instructions 📵

With Specific Instructions 👩‍🏫

Conclusion 🏁

Remove dead code for simplicity.

If you are uncertain of your code, you can temporarily disable it using Feature Toggle.

Removing code is always more rewarding than adding.

Relations 👩‍❤️‍💋‍👨

https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-xi-sit35t1

More Information 📕

HACKERNOONLaziness Chapter I: Meta-Programming | HackerNoonMeta-programming is magic. That is the main reason why we should not use it. There are many dire consequences on the horizon.

Credits 🙏

Photo by Ray Shrewsberry on Pixabay

This article is part of the CodeSmell Series.

HACKERNOONHow to Find the Stinky Parts of Your Code (Part I) | HackerNoonThe code smells bad. Let’s see how to change the aromas. In this series, we will see several symptoms and situations that make us doubt the quality of our developments. We will present possible solutions. Most of these smells are just hints of something that might be wrong. They are not rigid rules.