What are the core concepts covered in ES6 Classes, Inheritance & Prototype Chains?

How JavaScript's prototypal inheritance works under the hood; Class syntax: constructor, methods, getters, and setters; Extending base classes with extends and super()

Intermediate 18 min readModule: Module 9: Object-Oriented JS, Prototypes & Classes

ES6 Classes, Inheritance & Prototype Chains

Design modular object-oriented systems with ES6 classes, super constructors, and static methods.

What You Will Learn in This Lesson

How JavaScript's prototypal inheritance works under the hood
Class syntax: constructor, methods, getters, and setters
Extending base classes with extends and super()

Introduction & Core Concept

JavaScript classes provide clean syntactic sugar over prototype-based inheritance. Classes allow you to define structured blueprints for creating object instances.

WHY DOES THIS MATTER IN THE REAL WORLD?

Classes are widely used in backend ORMs, game development, and enterprise data models.

Class Hierarchy with Inheritance

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class User {
  constructor(name, email) {
    this.name = name;
    this.email = email;
  }
  getInfo() {
    return `${this.name} (${this.email})`;
  }
}
 
class AdminUser extends User {
  constructor(name, email, permissions) {
    super(name, email);
    this.permissions = permissions;
  }
}
 
const admin = new AdminUser("Kenneth", "ken@kwas.dev", ["ALL"]);
console.log(admin.getInfo());

Line-by-Line Technical Breakdown

1Every JavaScript object has an internal [[Prototype]] link to its parent prototype object.

Try It Yourself (Interactive Editor)

Modify the code in real-time and click Run to test live browser output and console logs.

Intelligent Code Runner & Live Sandbox[JAVASCRIPT]

JAVASCRIPT SOURCE EDITOR

Interactive Live Code

>Kenneth (ken@kwas.dev)

Industry Best Practices & Professional Standards

Use class syntax over manual Object.prototype mutation.

Lesson Summary & Core Takeaways

Classes provide clean, structured blueprints for object-oriented systems.