Learn JavaScript
Structured lessons from the basics up — follow the path below in order, at your own pace.
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1
Level 1 — Beginner Beginner 28 lessons
Start here if you have never written a line of JavaScript before. Work through these lessons in order — each one builds on the last.
Lessons in this module
What Is JavaScript? Why Learn JavaScript? Installing Node.js Setting Up Your Development Environment Your First JavaScript Program JavaScript Syntax Variables Data Types Numbers Strings Template Literals Boolean Values Operators Console Output Comments Conditional Statements if / else if / else Loops for Loops while Loops break / continue Arrays Objects Functions Arrow Functions Return Values Scope Basic Error Handling -
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Beginner Projects Beginner 1 lesson
Build these using only what Level 1 covered — variables, conditionals, loops, functions, and arrays/objects. Each is small enough to finish...
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Level 2 — Intermediate Intermediate 19 lessons
Once you're comfortable with variables, control flow, functions, and arrays/objects, these lessons cover how JavaScript is actually used to...
Lessons in this module
Classes and Objects Inheritance Encapsulation with Closures Polymorphism The this Keyword Exceptions Working with the DOM Handling Events Working with APIs and Fetch Working with JSON Promises Async/Await Node.js and npm Package Management Modules Testing Debugging Browser Storage Security Fundamentals -
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Intermediate Projects Intermediate 1 lesson
Prerequisites: Level 2 — Intermediate. Weather App Call a public weather API with fetch , and display the current temperature and conditions...
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Level 3 — Advanced Advanced 16 lessons
These lessons cover writing JavaScript for production: the event loop, advanced async patterns, architecture, and deployment.
Lessons in this module
Advanced Language Features The Event Loop and Concurrency Model Advanced Async Patterns Generators and Iterators Functional-Style JavaScript Design Patterns Architecture Build Tools and Bundlers Performance Optimization and Profiling Security Testing Strategies Package and Library Design API Design Server-Side JavaScript with Node Production Deployment and CI/CD Advanced Debugging -
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Advanced Projects Advanced 1 lesson
Prerequisites: Level 3 — Advanced. Full Stack Node/Express App A REST API Express with real data stored in a database, input validation, and...
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7
What You Should Know Now — and What's Next 1 lesson
What You Should Know Now Core syntax: variables, data types, conditionals, loops, functions Arrays and objects, plus modern destructuring/sp...