JavaScript Class Extension Lab: super

Learning Goals

• Practice using super to extend child class functionality

Introduction

In this lab we're going to practice the two most common usages of the super keyword.

Instructions

1. Define a Tree class that will act as our parent.

   • A Tree instance should take in one parameter when created, species, and assign this to a property named species.
   • A Tree should have a static method, definition(), that returns a short definition of all trees.

   A tree is a perennial plant with an elongated stem, or trunk, supporting branches and leaves.

2. Define a Deciduous class that extends Tree

   • A Deciduous instance takes two parameters, species and name. Use super() in the constructor to use the parent class constructor to assign species. After super(), assign the name parameter to the a name property in the Deciduous constructor
   • Create a static method, definition(), that uses super to access definition() from Tree and add the following to the provide a specific definition for Deciduous:

   Deciduous trees shed their leaves annually.

3. Define a Evergreen class that extends Tree

   • An Evergreen instance takes two parameters, species and name. Use super() in the constructor to use the parent class constructor to assign species, then assign name to a property in the Evergreen constructor
   • Create a static method, definition(), that uses super to access definition() from Tree and add the following to the provide a specific definition for Evergreen:

   Evergreens keep their leaves all year round.

Resources

• Static Methods
• “Super” and “Extends” In JavaScript ES6 - Understanding The Tough Parts