Modern JavaScript from the Beginning - Second Edition - Class Inheritance

The video tutorial explains the concept of classes and prototypes in JavaScript, highlighting the abstraction provided by classes. It demonstrates creating a basic shape class and extending it to form a Rectangle class, showcasing inheritance. The tutorial further explores using methods in subclasses and introduces polymorphism with a Circle class. It concludes with an explanation of prototypes and instance checking, emphasizing the importance of understanding these concepts in object-oriented programming.

What is one advantage of using classes over constructors and prototypes in JavaScript?

• Classes are faster to execute.

• Classes provide better abstraction.

• Classes are easier to debug.

• Classes use less memory.

Which keyword is used to inherit properties from a parent class in JavaScript?

• extends

• super

• prototype

• inherit

What is the purpose of the 'super' keyword in a subclass constructor?

• To call the constructor of the parent class.

• To call a method from the subclass.

• To override a method in the parent class.

• To create a new instance of the subclass.

How can you add a method to a class that can be used by its subclasses?

• By using the 'extends' keyword.

• By defining the method in the subclass.

• By using the 'super' keyword.

• By adding the method to the parent class.

What is polymorphism in the context of object-oriented programming?

• The ability to create multiple classes.

• The ability to inherit properties from a parent class.

• The ability to override methods in subclasses.

• The ability to use multiple constructors.

Which operator is used to check if an object is an instance of a specific class?

• classof

• typeof

• instanceof

• isInstance

What happens when you override a method in a subclass?

• The subclass method replaces the parent class method.

• Both methods are executed.

• The method in the subclass is ignored.

• The method in the parent class is deleted.