📊

Data Explorer

Master JavaScript data types, arrays, and objects. Learn strings, numbers, booleans, and how to organize data into collections.

Prerequisites:⚡JS Playground

Strings: Working with Text

Learn how JavaScript stores and manipulates text using strings — from creating them with quotes to combining and transforming them.

Numbers and Math

Master JavaScript's number type — arithmetic operators, rounding, and what happens when math goes wrong.

Booleans, null & undefined

Understand true/false values, comparison operators, and JavaScript's two ways of saying 'nothing.'

Type Coercion & typeof

Understand why JavaScript silently converts types, how to check types with typeof, and how to convert values explicitly.

Arrays: Ordered Lists

Learn how to store multiple values in a single variable using arrays — JavaScript's ordered, numbered lists.

Looping Through Arrays

Learn how to do something to every item in an array using for loops, .forEach(), and .map().

Objects: Named Properties

Learn how to group related data together using objects — JavaScript's key-value data structure.

Destructuring

Learn the shorthand syntax for unpacking values from arrays and objects into individual variables.

Capstone: Student Roster

Combine everything you've learned — strings, numbers, booleans, arrays, objects, loops, and template literals — to build a complete student roster system.

Codelab: Recipe Book Page

Build a real recipe book page from scratch — define recipe data with objects and arrays, then render it to the browser using JavaScript.