JavaScript

In JavaScript, classes were introduced in ES6 (ECMAScript 2015) to provide a more familiar and concise syntax for creating objects and handling inheritance compared to the traditional prototype-based approach. Classes in JavaScript are syntactic sugar over JavaScript’s existing prototype-based inheritance. A Quick Look at the Example What is Class Notation? Class notation is the modern…

Getters and setters are special functions used to get and set the values of an object’s properties. They allow you to control how properties are accessed and modified — providing encapsulation, validation, and computed properties. A Quick Look at the Examples a. Getters and Setters Introduction Getters and setters are special functions used to get…

Class inheritance allows you to create a new class that inherits properties and methods from an existing class. The new class (subclass/child) can reuse, extend, or override the behavior of the parent class (superclass/base). A Quick Look at the Example a. What is Class Inheritance? Inheritance is a mechanism where one class (the subclass or…

Method overriding is when a subclass provides its own implementation of a method that already exists in its parent class. The subclass’s method “takes over” — when called on an instance of the subclass, the new method runs instead of the parent’s. A Quick Look at the Example a. What is Method Overriding? Method overriding…

Polymorphism means “many forms” — it’s the ability of different classes to respond to the same method call in their own way. It’s one of the four pillars of object-oriented programming (along with encapsulation, inheritance, and abstraction). A Quick Look at the Example Key idea: animal.speak() looks identical for every animal, but produces a different…

The Iterator interface defines a standard way to access elements of a collection one at a time. It’s the mechanism that powers for…of loops, spread syntax, and destructuring in JavaScript. A Quick Look at the Example Key idea: An iterator is an object with a next() method that returns { value, done } on each…