JavaScript

15 lessons — from the very basics to pro-level patterns.

Basics
1. Variables & Data Types
let, const, and the types that live inside them
Beginner
2. Operators & Expressions
Math, logic, and the === vs == puzzle
Beginner
3. Strings & Template Literals
Backticks, interpolation, and handy methods
Beginner
4. Conditionals
if/else, switch, and the ternary shortcut
Beginner
5. Loops
for, while, and the modern for...of
Beginner
Collections
6. Arrays
The Swiss Army knife of JavaScript collections
Easy
7. Objects
Key-value pairs — the backbone of JS
Easy
Functions
8. Functions
Declarations, arrows, and closures
Easy
9. Array Higher-Order Methods
map, filter, reduce — loop without looping
Easy
Intermediate
10. DOM Manipulation
Make web pages come alive with JavaScript
Medium
11. Error Handling
try/catch and throwing your own errors
Medium
12. Classes & OOP
Blueprints for creating objects
Medium
13. Modules & Imports
import/export — keep your code organized
Medium
Advanced
14. Async Programming
Promises, async/await, and fetching data
Hard
15. Closures & Scope
How JavaScript remembers things
Hard