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Cover image for Code Smell 03 - Functions Are Too Long
Maxi Contieri
Maxi Contieri

Posted on • Updated on • Originally published at

Code Smell 03 - Functions Are Too Long

Humans get bored beyond line 10.

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


  • Low Cohesion
  • High coupling
  • Difficult to read
  • Low Reuse


1) Refactor

2) Create small objects dealing with some tasks. Unit test them.

3) Compose methods


  • Libraries

Sample Code



function setUpChessBoard() {

    //A lot of lines
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function setUpChessBoard() {
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All linters can measure and warn when methods are larger than a predefined threshold.


Also Known as

  • Long Method

More info


  • Complexity


Extract long method into smaller pieces. Break complex algorithms in parts. You can also unit test these parts.


Photo by Hari Panicker on Unsplash

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

Donald Knuth

This article is part of the CodeSmell Series.

Last update: 2021/06/01

Top comments (4)

joelbonetr profile image
JoelBonetR 🥇

The funny thing is that placeWhitePieces() and placeBlackPieces() will need to call each placement inside which then we'll need to separate into single functions placeKing($this) and get $this->color inside to keep them atomic.
So it's just a matter of ordering the code at the end.

mcsee profile image
Maxi Contieri

as always :)

winstonpuckett profile image
Winston Puckett

A developer I really respect said, "a developer can only hold one screen's worth of code at one time." And sets the function limit according to how big the average developer's screens are. I also like the way you said it, "humans get bored beyond line 10."

eduluz1976 profile image
Eduardo Luz

Sorry, but at first glance I didn't see any difference among the right and wrong code.