Currying as Process Design: Enforcing Order and Dependency

Top 10 Design Patterns Every Developer Must Know Design patterns are not theoretical concepts from computer science textbooks. They are solutions to problems you will encounter repeatedly in real production code. Recognizing which pattern applies and knowing how to implement it cleanly is one of the clearest markers of an experienced developer. Here are the 10 patterns you need to internalize: -> Singleton Pattern Ensures only one instance of a class exists throughout the entire application. Used for database connections, configuration managers, logging services, and anything that should not be duplicated. -> Factory Method Pattern Defines an interface for creating objects but lets subclasses decide which class to instantiate. Removes the need for the calling code to know exactly what type of object it is creating. -> Abstract Factory Pattern Creates families of related objects without specifying their concrete classes. Think UI component libraries that need to produce consistent sets of elements for different platforms. -> Builder Pattern Constructs complex objects step by step. Separates the construction of an object from its representation. Perfect for objects with many optional parameters where telescoping constructors become unreadable. -> Prototype Pattern Creates new objects by copying an existing object rather than creating from scratch. Useful when object creation is expensive and an existing instance can serve as a template. -> Observer Pattern Defines a one-to-many dependency so when one object changes state, all its dependents are notified automatically. This is the pattern behind event systems, reactive state management, and pub/sub architectures. -> Strategy Pattern Defines a family of algorithms, encapsulates each one, and makes them interchangeable. Lets the algorithm vary independently from the clients that use it. Use this when you have multiple ways to accomplish the same task. -> Decorator Pattern Attaches additional behavior to an object dynamically without modifying its class. Think middleware in Express, higher-order components in React, or adding toppings to a coffee order one layer at a time. -> Command Pattern Encapsulates a request as an object, allowing you to parameterize clients, queue requests, log them, and support undoable operations. Used in task schedulers, undo/redo systems, and transaction logs. These patterns solve problems that repeat across every codebase in every language. Learning them once means recognizing solutions across your entire career. Which of these patterns have you used most recently and in what context? #DesignPatterns #SoftwareEngineering #CleanCode #Programming #Developers #TechLeadership #BackendDevelopment

The SOLID principles, originally for object-oriented programming, are a set of five design guidelines that can be effectively applied to React to create more maintainable, scalable, and flexible applications. Here is how each principle translates to React development: Single Responsibility Principle (SRP): A component should have only one reason to change, meaning it should focus on a single task. In React: Separate concerns. For example, a component should focus solely on rendering UI, while data-fetching or complex state logic should be extracted to custom hooks or separate utility modules. Open/Closed Principle (OCP): Components should be open for extension but closed for modification. In React: Use props, children, and composition (wrapper components) to extend functionality rather than modifying a component's core logic or using many if/switch statements internally to handle different types. Liskov Substitution Principle (LSP): Subtypes must be substitutable for their base types without altering the correctness of the program. In React: Ensure components that share common functionality or prop types can be swapped without breaking the application. For instance, a PrimaryButton component should be able to replace a generic Button component wherever it's used without causing unexpected behavior. Interface Segregation Principle (ISP): Clients should not be forced to depend on interfaces (or props) they do not use. In React: Avoid "fat" components with numerous optional props. Design smaller, more focused components that only accept the data they require for their specific purpose. Dependency Inversion Principle (DIP): High-level modules should depend on abstractions, not concrete implementations. In React: Pass dependencies like API services, utility functions, or themes as props or through React's Context API or custom hooks, rather than hardcoding them within a component. This makes the component easier to test and more flexible, as the specific implementation can be easily swapped out. #React #SOLID #Frontend #JavaScript

💡 SOLID Principles Every Developer Should Know Writing code that works is easy. Writing code that is clean, scalable, and maintainable is the real challenge. That’s where the SOLID Design Principles help. These 5 principles are the foundation of good Low Level Design (LLD) and are widely used in real-world software architecture. Let’s quickly look at them 👇 🔹 Single Responsibility Principle (SRP) A class should have only one reason to change. 📖 Read more: https://lnkd.in/gQUPDhz6 🔹 Open/Closed Principle (OCP) Software should be open for extension but closed for modification. 📖 Read more: https://lnkd.in/gCPFMRYy 🔹 Liskov Substitution Principle (LSP) Subclasses should be able to replace their parent classes without breaking behavior. 📖 Read more: https://lnkd.in/gU9B-4uE 🔹 Interface Segregation Principle (ISP) Clients should not be forced to depend on methods they don't use. 📖 Read more: https://lnkd.in/gGCcgavA 🔹 Dependency Inversion Principle (DIP) Depend on abstractions, not concrete implementations. 📖 Read more: https://lnkd.in/gtAdWXWQ ⚡ Mastering SOLID helps you write code that is: ✔ Easier to maintain ✔ Easier to extend ✔ Easier to test ✔ Production-ready I’m documenting Low Level Design concepts with examples here: 🌐 https://www.revisealgo.in If you're learning System Design or preparing for interviews, these concepts are essential. 💬 Which SOLID principle do you use the most in your projects? #systemdesign #softwareengineering #cleanarchitecture #lowleveldesign #coding #programming #SOLID #developers #backenddevelopment

Design Principles and Patterns: Writing code that works is the starting point. Writing code that lasts, scales, and other developers can understand is the actual goal. That is what design principles and patterns give you. -> SOLID — the five principles every developer must internalize Single Responsibility: one class, one reason to change. When a class does too many things, changing one breaks the others. Open/Closed: extend behavior without modifying existing code. New features should not require rewriting what already works. Liskov Substitution: a subclass should be replaceable with its parent without breaking the system. If it cannot, your inheritance is wrong. Interface Segregation: small, focused interfaces over large general ones. Classes should not be forced to implement methods they do not need. Dependency Inversion: depend on abstractions, not concrete implementations. This is what makes code testable and swappable. -> GoF Design Patterns — battle-tested solutions to recurring problems Creational patterns solve how objects are created: Singleton, Factory, Builder, Prototype. Structural patterns solve how objects are composed: Adapter, Facade, Decorator, Proxy, Composite. Behavioral patterns solve how objects communicate: Observer, Strategy, Command, Iterator. -> DRY — Do Not Repeat Yourself Every piece of logic should exist in exactly one place. Duplication is not just inefficiency. It is a future bug waiting to happen. -> MVC — Model, View, Controller Separate your data layer from your UI from your request handling. Each layer has one job. This pattern scales from small applications to enterprise systems. -> KISS — Keep It Simple Complexity is the enemy of reliability. The simplest solution that solves the problem correctly is almost always the right solution. Design principles are not rules to follow mechanically. They are a vocabulary for making better decisions under pressure. Which of these principles do you find hardest to apply consistently in practice? #SoftwareEngineering #SOLID #DesignPatterns #CleanCode #Developers #Programming

𝗗𝗲𝘀𝗶𝗴𝗻 𝗧𝗵𝗶𝗻𝗸𝗶𝗻𝗴: 𝗔𝗯𝘀𝘁𝗿𝗮𝗰𝘁 𝗖𝗹𝗮𝘀𝘀 + 𝗦𝘁𝗮𝘁𝗶𝗰 𝗡𝗲𝘀𝘁𝗲𝗱 𝗖𝗹𝗮𝘀𝘀 (𝗝𝗮𝘃𝗮) — 𝗪𝗶𝘁𝗵 𝗘𝘅𝗮𝗺𝗽𝗹𝗲 Today I was exploring a design pattern used in many frameworks: **Abstract class with static nested class.** At first it looks like a simple Java feature, but actually this pattern is used for: * Hiding implementation * Controlled object creation * Wrapper design * Builder / Factory pattern * Framework-style API design ### Example ```java public abstract class PaymentProcessor { public abstract void processPayment(); // Static nested builder public static class Builder { public PaymentProcessor build() { return new DefaultPaymentProcessor(); } } // Hidden implementation private static class DefaultPaymentProcessor extends PaymentProcessor { @Override public void processPayment() { System.out.println("Processing payment..."); } } } ``` ### Usage ```java PaymentProcessor processor = new PaymentProcessor.Builder().build(); processor.processPayment(); ``` ### What this design tells User only sees: * PaymentProcessor (Abstraction) * Builder (Object creation) * processPayment() (API) User **cannot see or create DefaultPaymentProcessor directly**. Implementation is hidden and can be changed anytime without affecting users. This type of design is very common in frameworks and large systems where: **Abstraction is public, implementation is private, object creation is controlled.** ### Engineering Lesson In small projects we write code that works. In large systems we design code that: * Hides complexity * Controls object creation * Protects implementation * Exposes only abstraction * Allows future changes without breaking users **This is the difference between coding and software design.**

𝗗𝗮𝘆 𝟭𝟯/𝟵𝟬: 𝗔𝗿𝗰𝗵𝗶𝘁𝗲𝗰𝘁𝘂𝗿𝗲 𝟭𝟬𝟭 — 𝗜𝗻𝘁𝗿𝗼 𝘁𝗼 𝗗𝗲𝘀𝗶𝗴𝗻 𝗣𝗮𝘁𝘁𝗲𝗿𝗻𝘀 Today a I took a step back from syntax to look at the "Big Picture": 𝗗𝗲𝘀𝗶𝗴𝗻 𝗣𝗮𝘁𝘁𝗲𝗿𝗻𝘀. 𝗪𝗵𝗮𝘁 𝗮𝗿𝗲 𝘁𝗵𝗲𝘆? In software engineering, a Design Pattern is a proven, reusable solution to a commonly recurring problem. Think of them as 𝗯𝗹𝘂𝗲𝗽𝗿𝗶𝗻𝘁𝘀 for solving specific architectural challenges. Instead of reinventing the wheel, we use these established industry standards to write cleaner, more efficient code. 𝗧𝗵𝗲 𝟯 𝗣𝗶𝗹𝗹𝗮𝗿𝘀 𝗼𝗳 𝗗𝗲𝘀𝗶𝗴𝗻 𝗣𝗮𝘁𝘁𝗲𝗿𝗻𝘀 I’m diving into the three main categories that every Full Stack developer should know: 1️⃣ 𝗖𝗿𝗲𝗮𝘁𝗶𝗼𝗻𝗮𝗹 𝗣𝗮𝘁𝘁𝗲𝗿𝗻𝘀:   • These focus on Object Creation logic.   • They help decide how an object is created to avoid unnecessary      complexity (e.g., controlling how many instances exist).  • 𝗘𝘅𝗮𝗺𝗽𝗹𝗲𝘀: Singleton, Factory, Builder. 2️⃣ 𝗦𝘁𝗿𝘂𝗰𝘁𝘂𝗿𝗮𝗹 𝗣𝗮𝘁𝘁𝗲𝗿𝗻𝘀:   • These focus on Class & Object Composition.   • They help different parts of a system work together smoothly.  • 𝗘𝘅𝗮𝗺𝗽𝗹𝗲𝘀: Adapter, Decorator, Proxy. 3️⃣ 𝗕𝗲𝗵𝗮𝘃𝗶𝗼𝗿𝗮𝗹 𝗣𝗮𝘁𝘁𝗲𝗿𝗻𝘀:   • These focus on Communication between objects.   • They define how objects interact and share responsibilities.  • 𝗘𝘅𝗮𝗺𝗽𝗹𝗲𝘀: Observer, Strategy, Command. My next post will be a detailed breakdown of the most famous (and sometimes controversial) pattern: The Singleton Design Pattern.  Coding is about solving problems, but Engineering is about solving them sustainably.  Design patterns are the secret to building applications that last. 👨💻🔥 #90DaysOfCode #DesignPatterns #SoftwareArchitecture #Java #PentagonSpace #FullStackDeveloper #CreationalPatterns #CleanCode #SoftwareEngineering

We have all read the clean code books. We know the rules. Keep your functions small. Abstract everything. Use interfaces. But there is a trap that almost every developer falls into, and it is called over-engineering. I have seen pull requests where a simple feature that required updating three lines of logic was turned into a massive architecture of factories, builders, and strategy patterns. You open the code to see what it does, and you have to jump through five different files just to find the actual business logic. It is theoretically clean, it is perfectly decoupled, and it is absolutely impossible to read. Clean code is not about using every design pattern you learned in a tutorial. It is about making the code easy for the next person to understand and change. Sometimes, a single function with a basic if-else statement is infinitely better than a perfectly abstracted interface with three implementations. Every abstraction you add introduces cognitive load. You are trading immediate readability for future flexibility. But nine times out of ten, that "future flexibility" is never actually needed. The business requirements change in a completely different direction, and now you are stuck maintaining a complex architecture for a use case that never happened. The real senior developer secret is knowing when to stop abstracting. Simple, slightly repetitive code is almost always better than clever, highly abstracted code. Have you ever had to untangle a massive web of "clean" code just to fix a tiny bug? Let's discuss. 👇 #SoftwareEngineering #CleanCode #Backend #SystemDesign #Coding #Programming #DeveloperLife

Composition Over Inheritance — A powerful design principle Inheritance is one of the core features of Object-Oriented Programming. It allows classes to reuse behavior from a base class. However, excessive inheritance can make systems rigid and difficult to modify. When a subclass tightly depends on the behavior of a parent class, even small changes in the base class can unintentionally affect many other classes. This is why many developers prefer composition over inheritance. Instead of inheriting behavior from a parent class, a class can contain other classes and delegate work to them. Let's look at a simple example. ❌ Bad example (Using inheritance for behavior) public class Bird { public virtual void Fly() { Console.WriteLine("Flying..."); } } public class Penguin : Bird { public override void Fly() { throw new NotImplementedException("Penguins cannot fly"); } } Problem with this approach: • Penguins inherit a behavior they cannot perform • Breaks logical design • Leads to fragile class hierarchies • Violates good object-oriented design Now let's look at a better approach. ✅ Better example (Using composition) public interface IFlyBehavior { void Fly(); } public class CanFly : IFlyBehavior { public void Fly() { Console.WriteLine("Flying..."); } } public class CannotFly : IFlyBehavior { public void Fly() { Console.WriteLine("This bird cannot fly"); } } public class Bird { private readonly IFlyBehavior _flyBehavior; public Bird(IFlyBehavior flyBehavior) { _flyBehavior = flyBehavior; } public void PerformFly() { _flyBehavior.Fly(); } } Now behaviors can be changed or extended without modifying the class hierarchy. Benefits of composition: • More flexible design • Easier to extend behavior • Reduces tight coupling • Avoids deep inheritance hierarchies This approach is widely used in modern software architecture and design patterns. Still learning and exploring more about writing flexible and maintainable code. #softwareengineering #oop #softwaredesign #cleanarchitecture #dotnet

Design patterns are not spells to memorize They are tools for solving specific pain in your code One of the biggest mistakes I see developers make is collecting design patterns like trophies They learn Singleton Factory Strategy Observer Decorator Then they try to use them everywhere But patterns were never meant to be starting points They are responses to problems When you apply a pattern without understanding the pain first you do not improve the system You increase complexity Over engineering usually looks like this → Adding abstractions before they are needed → Creating interfaces with only one implementation → Introducing layers that do not solve a real constraint → Optimizing for flexibility that nobody requires → Making code harder to read in the name of being advanced Good engineers diagnose before they prescribe Before choosing a pattern ask yourself → What specific problem am I solving → What pain exists in the current design → Is duplication actually harmful here → Will this change simplify or complicate the system → Does the team understand this level of abstraction Patterns are valuable because they encode proven solutions But blindly applying them creates new problems that did not exist before The goal is not to show you know patterns The goal is to reduce complexity and improve clarity Simple code that solves the problem is better than clever code that impresses interviews Have you ever over engineered a solution because you wanted to use a pattern Or have you worked in a codebase where patterns made everything harder to understand Share your experience below Follow Nelson Djalo for practical lessons that help you think like a real software engineer #coding #softwareengineering #programming

Computer science 101 is to use design patterns for everything and even in university we get higher marks explicitly for using them. However, in practice, they end up introducing a lot of complexity due to the numerous abstraction layers. Don't get me wrong, they are very good for providing a structured way to solve the specific problem but they just need to be used in the right way. Before you start abstracting by creating abstract factories, just remember YAGNI (You Ain't Gonna Need It).