Part forty is here!!! It smells because there are likely many instances where it could be edited or improved. Most of these smells are just hints of something that might be wrong. Therefore, they are not required to be fixed per se… (You should look into it, though.) Previous Code Smells You can find all the previous code smells (Part i - ) . XXXIX here Let's continue... Code Smell 196 - Javascript Array Constructors Array creation is homogenous and predictable, or is it a hack? TL;DR: Be very careful with Javascript Arrays. Problems The Least surprise principle violation Solutions Be as declarative as possible Avoid creating Arrays with one argument. Context Javascript has a lot of magic tricks. Knowing them makes some developers proud and a sense of belonging to juniors. A language should be intuitive, homogeneous, predictable, simple, and pure. Sample Code Wrong const arrayWithFixedLength = new Array(3);

console.log(arrayWithFixedLength); // [ <5 empty items> ]
console.log(arrayWithFixedLength[0]); // Undefined
console.log(arrayWithFixedLength[1]); // Undefined
console.log(arrayWithFixedLength[3]); // Undefined
console.log(arrayWithFixedLength[4]); // Undefined
console.log(arrayWithFixedLength.length); // 3 Right const arrayWithTwoElements = new Array(3, 1);

console.log(arrayWithTwoElements); // [ 3, 1 ]
console.log(arrayWithTwoElements[0]); // 3
console.log(arrayWithTwoElements[1]); // 1
console.log(arrayWithTwoElements[2]); // Undefined
console.log(arrayWithTwoElements[5]); // Undefined
console.log(arrayWithTwoElements.length); // 2

const arrayWithTwoElementsLiteral = [3,1];

console.log(arrayWithTwoElementsLiteral); // [ 3, 1 ]
console.log(arrayWithTwoElementsLiteral[0]); // 3
console.log(arrayWithTwoElementsLiteral[1]); // 1
console.log(arrayWithTwoElementsLiteral[2]); // Undefined
console.log(arrayWithTwoElementsLiteral[5]); // Undefined
console.log(arrayWithTwoElementsLiteral.length); // 2 Detection Automatic [x] We can check for the notation with one argument and flag it as a warning. Tags Smart Conclusion Many "modern" languages are full of hacks to make life easier for programmers but are a source of potential undiscovered bugs. Relations Code Smell 06 - Too Clever Programmer Code Smell 69 - Big Bang (JavaScript Ridiculous Castings) Code Smell 93 - Send me Anything Disclaimer Code Smells are just my . opinion Credits Photo by on Ryan Quintal Unsplash Originally on this tweet: Twitter When someone says, "I want a programming language in which I need only say what I want done," give him a lollipop. Alan J. Perlis Software Engineering Great Quotes Code Smell 197 - Gratuitous Context TL;DR: Don't prefix or suffix your names with irrelevant information Problems Lack of Polymorphism Bad Naming violation with names Bijection Solutions Remove this context from your names Context In software development, gratuitous context refers to the unnecessary inclusion of additional information or data in code or user interfaces that do not contribute to the functionality or usability of the software. It can make the software more difficult to use, understand and maintain. It also increases the risk of errors or defects. Sample Code Wrong struct WEBBExoplanet {
    name: String,
    mass: f64, 
    radius: f64, 
    distance: f64, 
    orbital_period: f64, 
}

struct WEBBGalaxy {
    name: String,
    classification: String,
    distance: f64, 
    age: f64,
} Right struct Exoplanet {
    name: String,
    mass: f64, 
    radius: f64, 
    distance: f64, 
    orbital_period: f64, 
}

struct Galaxy {
    name: String,
    classification: String,
    distance: f64, 
    age: f64,
} Detection Semi-Automatic [x] We can find command patterns and rename all objects. Tags Naming Conclusion Class Preffixing was a widespread practice decades ago to claim ownership. Carefully consider the context and content of the software, and avoid including unnecessary or extraneous information wherever possible. Now we know clean names are more important. Relations Code Smell 141 - IEngine , AVehicle, ImplCar Code Smell 130 - AddressImpl Code Smell 174 - Class Name in Attributes More Info What exactly is a name - Part II Rehab Disclaimer Code Smells are my . opinion Credits Photo by on Mitchell Griest Unsplash The most dangerous kind of waste is the waste we do not recognize. Shigeo Shingo Code Smell 198 - Hidden Assumptions Software is about contracts and ambiguous contracts are a nightmare TL;DR: Keep your code explicit Problems Coupling Principle violation Fail Fast Fault Bijection Solutions Be declarative and explicit Don't oversimplify Context Hidden assumptions are underlying beliefs or expectations not explicitly stated in the code. They are still present and can impact the behavior of the software. Various reasons can give rise to assumptions such as incomplete requirements, incorrect presumptions about the user or environment, limitations of the programming language or tools, and bad accidental decisions. Sample Code Wrong tenCentimeters = 10
tenInches = 10

tenCentimeters + tenInches
# 20
# this error is based on the hidden assumption of a unit (any)
# and caused the Mars Climate Orbiter failure Right class Unit:
    def __init__(self, name, symbol):
        self.name = name
        self.symbol = symbol

class Measure:
    def __init__(self, scalar, unit):
        self.scalar = scalar
        self.unit = unit

    def __str__(self):
        return f"{self.scalar} {self.unit.symbol}"

centimetersUnit = Unit("centimeters", "cm")
inchesUnit = Unit("inches", "in")

tencCentimeters = Measure(10, centimeters)
tenInches = Measure(10, inches)

tenCentimeters + tenInches
# error until we introduce a conversion factor
# in this case the conversion is constant 
# inches = centimeters / 2.54 Detection Manual [x] This is a design smell Tags Coupling Conclusion Hidden assumptions can be difficult to identify and can lead to bugs, security vulnerabilities, and usability issues. To mitigate these risks, software developers should be aware of their assumptions and biases. Developers also need to engage with users to understand their needs and expectations. They must test their software in various scenarios to uncover hidden assumptions and edge cases. Relations Code Smell 02 - Constants and Magic Numbers More Info Mars Climate Orbiter Disaster Coupling - The one and only software design problem Measure Solution Disclaimer Code Smells are my . opinion Credits Photo by on Christian Pfeifer Unsplash A human organization is just as much an information system as any computer system. It is almost certainly more complex, but the same fundamental ideas apply. Things that are fundamentally difficult, like concurrency and coupling, are difficult in the real world of people, too. Dave Farley Code Smell 199 - Gratuitous Booleans A code that either returns or no returns at all TL;DR: Check carefully your boolean expressions Problems Readability Possible Defects Solutions Refactor and remove obsolete code Context When a function is designed to return an invariant value, it may be poor design, but it shouldn’t adversely affect the outcome of your program. However, when it happens on all paths through the logic, it is likely a mistake. This rule raises an issue when a function contains several return statements that all return the same value. Sample Code Wrong # Gratuitous boolean expressions

if a > 0 and True:
    print("a is positive")
else:
    print("a is not positive") Right if a > 0:
    print("a is positive")
else:
    print("a is not positive") Detection Automatic [x] Many can detect this problem by parsing execution trees. linters Tags Complexity Conclusion Boolean expressions should be straightforward to read and understand. Relations Code Smell 115 - Return True Code Smell 118 - Return False Code Smell 101 - Comparison Against Booleans More Info How to Get Rid of Annoying IFs Forever SonarSource Disclaimer Code Smells are just my . opinion Credits Photo by on Jungwoo Hong Unsplash The central enemy of reliability is complexity. Daniel Geer Code Smell 200 - Poltergeist An object that appears and disappears mysteriously TL;DR: Add the necessary indirection layers, but no more. Problems complexity Accidental Readability YAGNI violation Solutions Remove the intermediate object Context A poltergeist (or gypsy wagon) is a short-lived object used to perform initialization or to invoke methods in another, more permanent class. An object is responsible for many small tasks, resulting in excessive coupling and a lack of cohesion in the code. Sample Code Wrong public class Driver
{
    private Car car;

    public Driver(Car car)
    {
        this.car = car;
    }

    public void DriveCar()
    {
        car.driveCar();
    }
}

Car porsche = new Car();
Driver homer = new Driver(porsche);
homer.DriveCar(); Right Car porsche = new Car();

porsche.driveCar();
// We don't need the driver Detection Manual [x] This is a design smell. Tags Complexity Conclusion Don't add accidental complexity to the essential complexity we already have. Remove objects if they are not needed. middleman Relations Code Smell 54 - Anchor Boats Code Smell 67 - Middle Man More Info Wikipedia Disclaimer Code Smells are my . opinion Credits Photo by on Lan Gao Unsplash The art of programming is the art of organizing complexity, of mastering multitude and avoiding its bastard chaos as effectively as possible. E. W. Dijkstra 5 more code smells are coming soon…

The is an opinion piece based on the author’s POV and does not necessarily reflect the views of HackerNoon.

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