Article: Composition Alone Can't Replace Inheritance - strategy pattern

strategyPattern.js

class Monster {
  #onAttack
  constructor({ dropLoot, onAttack, customBehaviors = {} }) {
    this.dropLoot = dropLoot
    this.#onAttack = onAttack ?? (() => {})
    this.behaviors = customBehaviors
  }

  attack() {
    playHurtAnimation()
    this.#onAttack()
  }

  die() {
    userInventory.add(this.dropLoot())
    removeFromUi(this)
  }
}

const slimeBehavior = { ... }

const skeletonBehavior = { ... }

const clownBehavior = {
  dropLoot() {
    return [new Key()]
  },
  onAttack() {
    if (itsTime()) {
      showCutScene()
    }
  },
  customBehaviors: {
    uniqueClownBehavior() {
      ...
    }
  },
}
  
export const createSlime = () => new Monster(slimeBehavior)
export const createSkeleton = () => new Monster(skeletonBehavior)
export const createClown = () => new Monster(clownBehavior)