JavaScript Fundamentals

A beginner-to-advanced notebook covering modern JavaScript — variables, functions, arrays, objects, closures, asynchronous programming with promises and async/await, classes, ES modules, and the latest ECMAScript features through ES2024/ES2025. Pairs directly with the HTML Fundamentals and CSS Fundamentals notebooks to complete the core web trio.

Introduction to JavaScript

What is JavaScript?Adding JavaScript to HTML

Variables and Data Types

let, const, and var Primitive Data Types

Operators and Type Coercion

Arithmetic, Comparison, and Logical Operators Type Coercion and Conversion

Control Flow

Conditionals: if/else and switch Loops: for, while, and for...of

Functions Basics

Function Declarations and Expressions Arrow Functions and Default Parameters

Arrays and Array Methods

Working with Arrays Essential Array Methods: map, filter, reduce

Objects and Object Methods

Creating and Using Objects Object Methods and 'this'

Destructuring, Spread & Rest

Destructuring Arrays and Objects Spread and Rest Operators

Scope, Closures & this

Scope and the Scope Chain Closures Explained

Asynchronous JavaScript Basics

The Event Loop and Callbacks Promises Fundamentals

Async/Await and the Fetch API

Async/Await Syntax Fetching Data with the Fetch API

Classes and OOP

Classes, Constructors, and Inheritance Getters, Setters, and Private Fields

Modules and Modern Tooling

ES Modules: import and export Modern JavaScript Tooling Overview

Error Handling and Debugging

try/catch and Custom Errors Debugging with DevTools and the Console

Modern JavaScript Features (ES2020–ES2025)

Optional Chaining, Nullish Coalescing, and Logical Assignment Top-Level Await, Array Grouping, and the Latest ES Features