Tech & Engineering/12 min read

Composition Over Inheritance: A Practical Guide

Why composition leads to more flexible, maintainable code and how to apply it in real-world scenarios.

Artiphishle|January 10, 2026

patternsarchitectureoop

Composition Over Inheritance

One of the most valuable principles in software design.

The Problem with Deep Inheritance

1// This becomes a nightmare to maintain
2class Animal { }
3class Mammal extends Animal { }
4class Dog extends Mammal { }
5class ServiceDog extends Dog { }
6class PoliceServiceDog extends ServiceDog { }

Composition to the Rescue

1// Flexible and composable
2interface Behavior {
3  execute(): void
4}
5
6class BarkBehavior implements Behavior {
7  execute() { console.log(class="text-category-music">'Woof!') }
8}
9
10class Dog {
11  constructor(private behaviors: Behavior[]) {}
12  
13  performBehaviors() {
14    this.behaviors.forEach(b => b.execute())
15  }
16}

Build features by combining small, focused pieces rather than through inheritance chains.