Module 4 · 8 chapters

JavaScript Data Structures

Arrays and objects are how JavaScript represents real-world data — a list of products, a user profile, a configuration file. Understanding how to create, read, update, and iterate over these structures is essential for any project.

This module covers array methods like map and filter, object property access, destructuring assignment, the spread operator, and JSON — the format every REST API speaks. Visual memory diagrams show how references and copies behave so you avoid common mutation bugs.

Chapters in this module

ArraysJavaScript arrays store ordered lists of values — from shopping carts and todo items to rows in an API response. Learn zero-based indexing, push/pop/shift, length behavior, and why assigning an array copies a reference, not the data.
Array MethodsModern JavaScript rarely loops arrays by hand. Master map, filter, reduce, find, and forEach — the declarative toolkit for transforming data without accidentally mutating the original.
ObjectsObjects group related data under named keys — a user profile, app settings, or JSON payload from an API. Learn literal syntax, dot vs bracket access, nested structures, and how objects are stored on the heap.
Object MethodsLearn Object Methods in JavaScript — covering Defining Methods, The this Keyword, Getters & Setters, Built-in Object Methods with interactive visual examples and step-by-step explanations.
DestructuringDestructuring pulls values out of arrays and objects into standalone variables — swap elements, unpack API fields, and set defaults without repetitive temp = obj.a assignment chains.
Spread & RestLearn Spread & Rest in JavaScript — covering Spread: Arrays, Spread: Objects, Rest Parameters, Rest in Destructuring with interactive visual examples and step-by-step explanations.
JSONLearn JSON in JavaScript — covering What is JSON?, JSON.stringify(), JSON.parse(), Working with APIs with interactive visual examples and step-by-step explanations.
StringsLearn Strings in JavaScript — covering String Basics, Template Literals, String Methods, Immutability with interactive visual examples and step-by-step explanations.

Start with Arrays