Code Smell 115 — Return True

Booleans are natural code smells. Returning and casting them is sometimes a mistake

Photo by engin akyurt on Unsplash

TL;DR: Don’t return true or false. Be declarative.

Problems

• Readability
• Primitive Obsession
• If/Else abuse

Solutions

1. Return truth value in a declarative way.

2. Replace IFs With polymorphism.

Context

Dealing with low-level abstractions, we usually return booleans.

When we create complex and mature software, we start to forget about this primitive obsession and care about real-world rules and identities.

Sample Code

Wrong

boolean isEven(int num){
     if(num%2 == 0){
       return true;   
     } else {  
       return false;
     }
}

Right

boolean isEven(int numberToCheck){
  //We decouple the what (to check for even or odd)
  //With how (the algorithm)  
     return (numberToCheck % 2 == 0); 
}

Detection

[X] Automatic

Many linters can check syntactic trees and look for explicit true/value returns.

Tags

• Primitive

Conclusion

Search on code libraries for *return true* statements and try to replace them when possible.

Relations

Code Smell 118 — Return False

Code Smell 36 — Switch/case/elseif/else/if statements

More Info

How to Get Rid of Annoying IFs Forever

The one and only software design principle

The good news is: Anything is possible on your computer. The bad news is: Nothing is easy.

Ted Nelson

Software Engineering Great Quotes

This article is part of the CodeSmell Series.

How to Find the Stinky parts of your Code