Code Smell 03: Functions Are Too Long - Here's How to Fix That

Humans get bored after line five.

TL;DR: Refactor and extract functions longer than 5 lines.

Problems 😔

• Low cohesion
• High coupling
• Hard to read
• Low reusability

Solutions 😃

1. Refactor
2. Create small objects to handle specific tasks. Unit-test them.
3. Compose methods
4. Divide and conquer

Refactorings ⚙️

https://maximilianocontieri.com/refactoring-010-extract-method-object?embedable=true

https://hackernoon.com/refactoring-025-decompose-regular-expressions?embedable=true

https://hackernoon.com/improving-the-code-one-line-at-a-time?embedable=true

Examples

• Libraries

Context 💬

When you write a long function, you hide too many details in one place.

You force the reader to hold multiple concepts in mind.

You mix unrelated responsibilities and make the code hard to test.

You create a rigid block that breaks easily when you change it.

Short, focused functions let you read, test, and modify code faster.

Sample Code 📖

Wrong 🚫

<?

function setUpChessBoard() {
    $this->placeOnBoard($this->whiteTower);
    $this->placeOnBoard($this->whiteKnight);
    // A lot more lines
    
    // Empty space to pause definition
    $this->placeOnBoard($this->blackTower);
    $this->placeOnBoard($this->blackKnight);
    // A lot more lines
}

Right 👉

<?

function setUpChessBoard() {
    $this->placeWhitePieces();
    $this->placeBlackPieces();
}

Detection 🔍

• [x]Automatic

All linters can measure and warn when methods exceed a predefined threshold.

Tags 🏷️

• Bloaters

Level 🔋

• [x]Beginner

Why the Bijection Is Important 🗺️

A real-world action should map to a clear, concise function.

When you pack many actions into one function, you lose that mapping.

Developers must mentally reconstruct the steps, which slows comprehension and increases errors.

AI Generation 🤖

AI generators often create long functions if you give them vague prompts.

They tend to cram all logic into one place unless you explicitly request modular code.

AI Detection 🥃

AI tools can fix this smell with the right instructions to split code into small, focused functions.

Try Them! 🛠

Remember: AI Assistants make lots of mistakes

Suggested Prompt: Convert it to more declarative

Conclusion 🏁

Extract long methods into smaller pieces.

Break complex algorithms into parts.

You can also unit test these parts.

Relations 👩‍❤️‍💋‍👨

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

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

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

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

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

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

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

More Information 📕

https://refactoring.guru/es/smells/long-method?embedable=true

Also Known as

• Long Method

Credits 🙏

Photo by Hari Panicker on Unsplash

Programs are meant to be read by humans and only incidentally for computers to execute.

Donald Knuth

https://hackernoon.com/400-thought-provoking-software-engineering-quotes?embedable=true

This article is part of the CodeSmell Series.

https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-i-xqz3evd?embedable=true