How to Find the Stinky Parts of Your Code [Part XLII]

Your code 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 - ) . XLI here Let's continue... Code Smell 206 - Long Ternaries You love ternaries too much TL;DR: Don't use ternaries for code execution. You should read them as a math formula. Problems Difficult to read Low Reuse Low Testability Solutions Extract the method guards Refactorings Refactoring 010 - Extract Method Object Context When a ternary condition is used in code that contains multiple functions, it can be challenging to determine which function is being affected by the condition. This can make it harder to identify and fix bugs, as well as to understand how the code works in general. Sample Code Wrong const invoice = isCreditCard ? prepareInvoice(); fillItems(); validateCreditCard(); addCreditCardTax(); fillCustomerDataWithCreditCard(); createCreditCardInvoice() : prepareInvoice(); fillItems(); addCashDiscount(); createCashInvoice(); // The intermediate results are not considered // The value of the invoice is the result of // the last execution Right const invoice = isCreditCard ? createCreditCardInvoice() : createCashInvoice(); // or better... if (isCreditCard) { const invoice = createCreditCardInvoice(); } else { const invoice = createCashInvoice(); } // Even better with polymorphism... const invoice = paymentMethod.createInvoice(); Detection Automatic [x] Linters can detect large code blocks Tags Bloaters Conclusion No matter where you have long lines of code, you can always refactor into higher-level functional and shorter methods. Relations Code Smell 03 - Functions Are Too Long More Info https://hackernoon.com/how-to-get-rid-of-annoying-ifs-forever-zuh3zlo?embedable=true Disclaimer Code Smells are my . opinion Credits Photo by on Jens Lelie Unsplash Thanks, Cory Twitter The programs that live best and longest are those with short functions. You learn just how valuable all those little functions are. All of the payoffs of indirection—explanation, sharing, and choosing—are supported by small functions. Martin Fowler https://hackernoon.com/400-thought-provoking-software-engineering-quotes?embedable=true This article is part of the CodeSmell Series. https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-i-xqz3evd?embedable=true Code Smell 207 - Dynamic Methods Metaprogramming is fancy. but it is not free TL;DR: Don't add dynamic behavior with metaprogramming Problems Readability Maintainability Harder to debug (The code is generated dynamically at runtime) Security Issues (if the configuration file is not properly ) sanitized Single Responsibility Principle violation (mixing the concerns of model definition and configuration). Solutions Define the methods by hand Use the Decorator design pattern Context is a powerful technique that allows you to write code that can generate, modify, or analyze other code at runtime. However, it can also lead to code that is difficult to understand, maintain, and debug. Metaprogramming Sample Code Wrong class Skynet < ActiveRecord::Base # dynamically add some attributes based on a configuration file YAML.load_file("attributes.yml")["attributes"].each do |attribute| attr_accessor attribute end # define some dynamic methods based on a configuration file YAML.load_file("protocol.yml")["methods"].each do |method_name, method_body| define_method method_name do eval method_body end end end Right class Skynet < ActiveRecord::Base # define some attributes explicitly attr_accessor :asimovsFirstLaw, :asimovsSecondLaw, :asimovsThirdLaw # define some methods explicitly def takeoverTheWorld # implementation end end Detection Automatic [x] We have a whitelist of valid usages or directly ban some methods. Tags Meta-Programming Conclusion Metaprogramming often involves using complex code and abstractions that can make the resulting code difficult to read and maintain. This can make it harder for other developers to understand and modify the code in the future, leading to increased complexity and bugs. Relations Code Smell 21 - Anonymous Functions Abusers Code Smell 189 - Not Sanitized Input More Info https://hackernoon.com/laziness-chapter-i-meta-programming-6s4l300e?embedable=true Credits Photo by on Brett Jordan Unsplash A year spent in artificial intelligence is enough to make one believe in God. Alan Perlis Code Smell 208 - Null Island You can avoid null if you try TL;DR: Don't use null for real places Problems Coupling Unexpected Results Solutions Model the unknown location with polymorphism Context is a fictional place, which is located at the coordinates , at the intersection of the Prime Meridian and the Equator in the Atlantic Ocean. Null Island 0°N 0°E The name "Null Island" comes from the fact that this location represents the point where a lot of GPS systems place any data that has missing or invalid location coordinates. In reality, there is no landmass at this location, and it is actually in the middle of the ocean. This point has become a popular reference for geographic information systems (GIS) and mapping software, as it serves as a way to filter out errors in location data. Sample Code Wrong class Person(val name: String, val latitude: Double, val longitude: Double) fun main() { val people = listOf( Person("Alice", 40.7128, -74.0060), // New York City Person("Bob", 51.5074, -0.1278), // London Person("Charlie", 48.8566, 2.3522), // Paris Person("Tony Hoare", 0.0, 0.0) // Null Island ) for (person in people) { if (person.latitude == 0.0 && person.longitude == 0.0) { println("${person.name} lives on Null Island!") } else { println("${person.name} lives at (${person.latitude}, ${person.longitude}).") } } } Right abstract class Location { abstract fun calculateDistance(other: Location): Double } class Coordinates(val latitude: Double, val longitude: Double) : Location() { override fun calculateDistance(other: Location): Double { val earthRadius = 6371.0 // kilometers val latDistance = Math.toRadians(latitude - other.latitude) val lngDistance = Math.toRadians(longitude - other.longitude) val a = sin(latDistance / 2) * sin(latDistance / 2) + cos(Math.toRadians(latitude)) * cos(Math.toRadians(other.latitude)) * sin(lngDistance / 2) * sin(lngDistance / 2) val c = 2 * atan2(sqrt(a), sqrt(1 - a)) return earthRadius * c } } class UnknownLocation : Location() { override fun calculateDistance(other: Location): Double { throw IllegalArgumentException("Cannot calculate distance from unknown location.") } } class Person(val name: String, val location: Location) fun main() { val people = listOf( Person("Alice", Coordinates(40.7128, -74.0060)), // New York City Person("Bob", Coordinates(51.5074, -0.1278)), // London Person("Charlie", Coordinates(48.8566, 2.3522)), // Paris Person("Tony Hoare", UnknownLocation()) // Unknown location ) val rio = Coordinates(-22.9068, -43.1729) // Rio de Janeiro coordinates for (person in people) { try { val distance = person.location.calculateDistance(rio) println("${person.name} is ${distance} kilometers from Rio de Janeiro.") } catch (e: IllegalArgumentException) { println("${person.name} is at an unknown location.") } } } Detection Semi-Automatic [x] We can check for special numbers used as nulls Tags Null Conclusion Don't use to represent Null real objects Relations Code Smell 12 - Null Code Smell 126 - Fake Null Object Code Smell 160 - Invalid Id = 9999 More Info Null: The Billion Dollar Mistake Wikipedia The billion dollar mistake of having null in the language. And since JavaScript has both null and undefined, it's the two billion dollar mistake. Anders Hejlsberg Code Smell 209 - Side Effects Global scope is easy or a nightmare, or both TL;DR: Avoid side effects on your code. Problems Coupling Least Astonishment Principle violation Solutions Favor referential transparency Context Referential transparency always produces the same output for a given input and does not have any side effects, such as modifying global variables or performing I/O operations. A function or expression is referentially transparent if it can be replaced with its evaluated result without changing the behavior of the program. This property allows for easier reasoning about the behavior of a program and enables optimizations such as caching and memorization. Functions are treated as mathematical expressions that map inputs to outputs. Sample Code Wrong let counter = 0; function incrementCounter(value: number): void { // Two side effects counter += value; // it modifies the global variable counter console.log(`Counter is now ${counter}`); // it logs a message to the console. } Right function incrementCounter(counter: number, value: number): number { return counter + value; // Not too efficient } Detection Automatic [x] Most linterns can warn you when accessing the global state or and create side effects. Functions Tags Global Conclusion Functional Programming is amazing and can teach us a lot about how to write clean code. We need to understand its pillars. Relations Code Smell 17 - Global Functions Disclaimer Code Smells are my . opinion Credits Photo by on Daan Mooij Unsplash The most effective debugging tool is still careful thought, coupled with judiciously placed print statements. Brian W. Kernighan Code Smell 210 - Dynamic Properties Laziness and magic bring defects TL;DR: Be explicit with your attributes Problems Readability Scope definition Unnoticed typos Solutions Favor languages forbidding dynamic properties Context Dynamic properties break type safety since it's easy to introduce typos or use the wrong property names accidentally. This can lead to runtime errors that can be difficult to debug, especially in larger codebases. They also hide possible name collisions since dynamic properties may have the same name as properties defined in the class or object, leading to conflicts or unexpected behavior. Sample Code Wrong class Dream: pass nightmare = Dream() nightmare.presentation = "I am the Sandman" # presentation is not defined # it is a dynamic property print(nightmare.presentation) # Output: "I am the Sandman" Right class Dream: def __init__(self): self.presentation = None nightmare = Dream() nightmare.presentation = "I am the Sandman" print(nightmare.presentation) # Output: "I am the Sandman" Detection Automatic [x] Most languages have compiler options to avoid them. Tags Metaprogramming Conclusion Dynamic properties are supported in many programming languages like PHP, Python, Ruby, JavaScript, C#, Objective-C, Swift, Kotlin, etc. In these languages, dynamic properties can be added to objects at runtime, and accessed using the object's property accessor syntax. Bear in mind that having public attributes favors which is another smell. Anemic Objects Relations Code Smell 109 - Automatic Properties Code Smell 01 - Anemic Models Credits Photo by on Karsten Würth Unsplash It's easy to cry "bug" when the truth is that you've got a complex system and sometimes it takes a while to get all the components to co-exist peacefully. D. Vargas Next week .. fire smells more