Constructors and super() Lesson

Constructor chaining means a child class constructor calls the parent class constructor. In JavaScript, this happens with super. The parent handles the shared setup, and the child adds extra details afterward. A child constructor must call super before using this. That rule exists because the parent constructor creates the base part of the object.

Code Runner Challenge

Constructors and super() Lesson

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%%js

// CODE_RUNNER: Constructors and super() Lesson

class Item {
  constructor(name, value) {
    this.name = name;
    this.value = value;
  }
}

class Weapon extends Item {
  constructor(name, value, damage) {
    super(name, value);
    this.damage = damage;
  }
}

const sword = new Weapon("Iron Sword", 25, 8);
console.log(sword.name + " does " + sword.damage + " damage");

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Output

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Weapon calls super to reuse the Item setup for name and value. After that, it adds the damage property that only weapons need.