# Use of Super

In JavaScript, the super keyword is used to call the parent class's constructor or a method from the child class. For example, consider the following code:

```javascript
class Animal {
  constructor(name) {
    this.name = name;
  }

  speak() {
    console.log(`${this.name} makes a noise.`);
  }
}

class Cat extends Animal {
  constructor(name, breed) {
    super(name);
    this.breed = breed;
  }

  speak() {
    console.log(`${this.name} meows.`);
  }
}

const cat = new Cat('Fluffy', 'Siamese');
cat.speak();
// Output: "Fluffy meows."
```

In this example, the `Cat` class extends the `Animal` class and overrides the `speak` method. The `Cat` class also has a constructor that accepts a `name` and a `breed` parameter. In the `Cat` constructor, we use the `super` keyword to call the `Animal` constructor and pass it the `name` argument. This sets the `name` property of the `Cat` instance to the value of the `name` argument.

The `super` keyword can also be used to call a method of the parent class from the child class. For example, we could modify the `speak` method of the `Cat` class to call the `speak` method of the `Animal` class like this:

```javascript
class Cat extends Animal {
  // ...

  speak() {
    super.speak();
    console.log(`${this.name} meows.`);
  }
}
```

This would cause the `Cat` instance to make both a noise (using the `speak` method from the `Animal` class) and meow (using the `speak` method from the `Cat` class).