Favor Composition Over Inheritance

Deep inheritance chains are brittle. When requirements change, you end up fighting the hierarchy.

// dirty — inheritance chain
class Animal {
  constructor(public name: string) {}
}
class Dog extends Animal {
  bark(): string { return this.name + ' says: woof'; }
}
class Cat extends Animal {
  meow(): string { return this.name + ' says: meow'; }
}

Refactor using composition: create createAnimal(name, sound) that returns an object with a speak() method. No classes, no inheritance.
solve(name, sound) calls createAnimal(name, sound).speak().

solve('Rex', 'woof') → 'Rex says: woof'