Code Smell 201 - Nested Ternaries

Arrow Code, Nested Conditions, switches, else, and many more

TL;DR: Don't use nested IFs or nested ternaries

Problems

• Readability

• Default Case

Solutions

1. Rewrite the code as an IF condition with an early return

Context

Nesting is always a problem with complexity.

We can fix it with polymorphism or early returns

Sample Code

Wrong

const getUnits = secs => (
 secs <= 60       ? 'seconds' :
 secs <= 3600     ? 'minutes' :
 secs <= 86400    ? 'hours'   :
 secs <= 2592000  ? 'days'    :
 secs <= 31536000 ? 'months'  :
                    'years' 
)

Right

const getUnits = secs => {
 if (secs <= 60) return 'seconds'; 
 if (secs <= 3_600) return 'minutes'; 
 if (secs <= 86_400) return 'hours';   
 if (secs <= 2_592_000) return 'days';    
 if (secs <= 31_536_000) return 'months';  
 return 'years' 
}

// More declarative

const getUnits = secs => {
 if (secs <= 60) return 'seconds'; 
 if (secs <= 60 * 60) return 'minutes'; 
 if (secs <= 24 * 60 * 60) return 'hours';   
 if (secs <= 30 * 24 * 60 * 60) return 'days';    
 if (secs <= 12 * 30 * 24 * 60 * 60) return 'months';  
 return 'years' 
}

Detection

[X] Automatic

Linters can detect this complexity using parsing trees.

Tags

• IFs

Conclusion

We must deal with accidental complexity to improve code readability.

Relations

Code Smell 133 - Hardcoded IF Conditions

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Code Smell 78 - Callback Hell

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Code Smell 102 - Arrow Code

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Disclaimer

Code Smells are my opinion.

Credits

Photo by NIKHIL on Unsplash

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One of the best things to come out of the home computer revolution could be the general and widespread understanding of how severely limited logic really is.

Frank Herbert

Software Engineering Great Quotes

Maxi Contieri ・ Dec 28 '20

#codenewbie #programming #quotes #software

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This article is part of the CodeSmell Series.

How to Find the Stinky parts of your Code

Maxi Contieri ・ May 21 '21

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