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Code Smell 03 - Functions Are Too Long

Humans get bored beyond line 10.

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

Problems

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

Solutions

1. Refactor

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

3. Compose methods

Refactorings

Refactoring 010 - Extract Method Object

Examples

• Libraries

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

All linters can measure and warn when methods are larger than a predefined threshold.

Relations

Code Smell 75 - Comments Inside a Method

Code Smell 102 - Arrow Code

Code Smell 206 - Long Ternaries

Tags

• Complexity

Conclusion

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

Also Known as

• Long Method

More Info

Refactoring Guru

Credits

Photo by Hari Panicker on Unsplash

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

Donald Knuth

Software Engineering Great Quotes

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This article is part of the CodeSmell Series.

How to Find the Stinky Parts of your Code