This content originally appeared on HackerNoon and was authored by Maximiliano Contieri
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 😃
- Refactor
- Create small objects to handle specific tasks. Unit-test them.
- Compose methods
- 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
| Without Proper Instructions | With Specific Instructions | |----|----| | ChatGPT | ChatGPT | | Claude | Claude | | Perplexity | Perplexity | | Copilot | Copilot | | You | You | | Gemini | Gemini | | DeepSeek | DeepSeek | | Meta AI | Meta AI | | Grok | Grok | | Qwen | Qwen |
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
\
This content originally appeared on HackerNoon and was authored by Maximiliano Contieri
Maximiliano Contieri | Sciencx (2025-08-20T13:00:08+00:00) Code Smell 03: Functions Are Too Long – Here’s How to Fix That. Retrieved from https://www.scien.cx/2025/08/20/code-smell-03-functions-are-too-long-heres-how-to-fix-that/
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