Maxi Contieri

Posted on Jan 27, 2023 • Originally published at maximilianocontieri.com

Code Smell 193 - Switch Instead of Formula

#webdev #javascript #beginners #programming

Which is better, declarative or shorter code?

TL;DR: Be declarative enough but no more.

Problems

Readability
Premature Optimization

Solutions

Use a short version (or not).
Always favor readability >> Premature optimization.
Humans learn by examples, not by formulas.
Shorter is not always better.

Context

Last week, a tweet went viral because of a missing formula.

It is the DigiD digital authentication iOS app in the Netherlands.

Sample Code

Wrong?

private static string GetPercentageRounds(double percentage)
        {
            if (percentage == 0)
                return "⚪⚪⚪⚪⚪⚪⚪⚪⚪⚪";
            if (percentage > 0.0 && percentage <= 0.1)
                return "🔵⚪⚪⚪⚪⚪⚪⚪⚪⚪";
            if (percentage > 0.1 && percentage <= 0.2)
                return "🔵🔵⚪⚪⚪⚪⚪⚪⚪⚪";
            if (percentage > 0.2 && percentage <= 0.3)
                return "🔵🔵🔵⚪⚪⚪⚪⚪⚪⚪";
            if (percentage > 0.3 && percentage <= 0.4)
                return "🔵🔵🔵🔵⚪⚪⚪⚪⚪⚪";
            if (percentage > 0.4 && percentage <= 0.5)
                return "🔵🔵🔵🔵🔵⚪⚪⚪⚪⚪";
            if (percentage > 0.5 && percentage <= 0.6)
                return "🔵🔵🔵🔵🔵🔵⚪⚪⚪⚪";
            if (percentage > 0.6 && percentage <= 0.7)
                return "🔵🔵🔵🔵🔵🔵🔵⚪⚪⚪";
            if (percentage > 0.7 && percentage <= 0.8)
                return "🔵🔵🔵🔵🔵🔵🔵🔵⚪⚪";
            if (percentage > 0.8 && percentage <= 0.9)
                return "🔵🔵🔵🔵🔵🔵🔵🔵🔵⚪";

            return "🔵🔵🔵🔵🔵🔵🔵🔵🔵🔵";
        }
    }
}

// Full source
// https://github.com/MinBZK/woo-besluit-broncode-digid-app/blob/master/Source/DigiD.iOS/Services/NFCService.cs

Right?

private static string GetPercentageRounds(double percentage)
{
    string dots = "🔵🔵🔵🔵🔵🔵🔵🔵🔵🔵⚪⚪⚪⚪⚪⚪⚪⚪⚪⚪";
    int blueDots = (int) Math.Truncate (percentage* 10);
    int startingPoint = 10-blueDots;
    return dots. Substring(startingPoint, 10);
}

Detection

[X] Semi-Automatic

This is a semantic smell. In this case, we can count the number of if clauses.

Conclusion

You can read the original Twitter thread to take your own conclusions. There's some serious debate and, of course, several premature optimizators bringing obscure and unneeded solutions with (O) log(n) complexity and stupid benchmarks evidence for a loop that executes only once.

And lots of memes.

As a final conclusion, I asked ChatGPT and was not able to simplify it.

Relations

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

Maxi Contieri ・ Nov 28 '20

#oop #webdev #tutorial #codenewbie

Code Smell 20 - Premature Optimization

Maxi Contieri ・ Nov 8 '20

#oop #developing #coding #codesmell

More Info

GitHub Repo

How to Get Rid of Annoying IFs Forever

Maxi Contieri ・ Nov 9 '20

#oop #programming #codenewbie #tutorial

Disclaimer

Code Smells are just my opinion.

There are two ways of constructing a software design. One way is to make it so simple that there are obviously no deficiencies. And the other way is to make it so complicated that there are no obvious deficiencies.

C. A. R. Hoare

Software Engineering Great Quotes

Maxi Contieri ・ Dec 28 '20

#codenewbie #programming #quotes #software

This article is part of the CodeSmell Series.

How to Find the Stinky parts of your Code

Maxi Contieri ・ May 21 '21

#codenewbie #tutorial #codequality #beginners

Oldest comments (7)

Ben Sinclair • Jan 28 '23

The thing that confused me most about this function is the fact that the parameter is called percentage but it's not a percentage.

It'll work if you pass a percentage like 37.5 or even 200.0, but it'll only display anything other than ten dots if it's < 1%.

Maybe that's what the code is supposed to do... but I doubt it!

lionel-rowe • Jan 28 '23 • Edited

Why not just programmatically repeat the relevant glyphs the required number of times? Returning a substring of a string containing 10 of each glyph is a bit too magic for my liking, and difficult to see at-a-glance if you've miscounted.

private static string GetPercentageRounds(double fraction) {
    int max = 10;
    string on = "🔵";
    string off = "⚪";

    int numDots = (int) Math.Ceiling(fraction * max);

    return string.Concat(Enumerable.Repeat(on, numDots))
        + string.Concat(Enumerable.Repeat(off, max - numDots));
}

Maxi Contieri • Jan 28 '23

This code is less declarative than the original one. It is very hard to understand what is doing without running it on your head

lionel-rowe • Jan 29 '23

I don't usually use C#, I just saw that string.Concat(Enumerable.Repeat(str, num)) is the idiomatic way to repeat a string in C# (as opposed to repeating a char, and '🔵' isn't a valid char due to being 2 code-units in UTF-16).

You could always split that into its own function:

private static string RepeatStr(string str, int num) {
    return string.Concat(Enumerable.Repeat(str, num));
}

private static string GetPercentageRounds(double fraction) {
    int max = 10;
    string on = "🔵";
    string off = "⚪";

    int numDots = (int) Math.Ceiling(fraction * max);

    return RepeatStr(on, numDots) + RepeatStr(off, max - numDots);
}

Maxi Contieri • Jan 30 '23

still less declarative

lionel-rowe • Jan 31 '23

Under what definition of "declarative"? There's no explicit control flow whatsoever (whereas the original has 10 if statements, lol). What do you understand "declarative" to mean if it's not lack of explicit control flow?