JavaScript

roadmap.sh: https://roadmap.sh/javascript

Suggested path through the JavaScript nodes. Each node links to its lesson when written.

Nodes

Introduction

• What is JavaScript
• History of JavaScript
• JavaScript versions (ECMAScript)
• How to run JavaScript

All about Variables

• var, let and const
• Hoisting
• Variable naming rules
• Variable scopes (global, block, lexical)

Data Types

• Primitive types
• Number
• BigInt
• String
• Boolean
• Null
• Undefined
• Symbol
• Object
• typeof operator

Type Casting

• Explicit type casting
• Implicit type casting (coercion)
• Type conversion vs coercion

Data Structures

• Keyed collections (Map, WeakMap, Set, WeakSet)
• Indexed collections (Arrays, typed arrays)
• Structured data (JSON)

Equality Comparisons

• Value comparison operators
• Equality () vs strict equality (=)
• Object.is()

Loops and Iterations

• for
• do…while
• while
• for…in
• for…of
• break / continue

Control Flow

• Conditional statements (if…else, switch)
• Exception handling (try/catch/finally)
• Error objects

Expressions and Operators

• Assignment operators
• Comparison operators
• Arithmetic operators
• Bitwise operators
• Logical operators
• BigInt operators
• String operators
• Conditional (ternary) operator
• Comma operator
• Unary operators
• Relational operators

Functions

• Defining functions
• Function parameters & default params
• Arrow functions
• IIFEs
• arguments object
• Scope and function stack (recursion)
• Built-in functions

this Keyword

• this in a method
• this in a function
• this in arrow functions
• this in event handlers
• Explicit binding (call, apply, bind)
• Function borrowing

Asynchronous JavaScript

• Event loop
• Callbacks
• Callback hell
• Promises
• async/await
• setTimeout / setInterval
• fetch API

Classes

• Class syntax
• Constructor
• Inheritance (extends, super)
• Static methods & properties
• Private fields

Iterators and Generators

• Iterators
• Generators
• Iteration protocols

Modules

• CommonJS
• ECMAScript Modules (ESM)
• Import / export

Working with APIs

• DOM APIs
• Fetch & XMLHttpRequest
• JSON parsing & serialization

Closures

• Lexical scoping
• Closures in practice

Memory Management

• Memory lifecycle
• Garbage collection

Using Browser DevTools

• Debugging issues
• Debugging memory leaks
• Debugging performance

Resources

See resources.md.

Project ideas

• Build a vanilla-JS to-do app with localStorage persistence and no frameworks.
• Write a small Promise-based fetch wrapper with retry, timeout, and cancellation.
• Implement a debounce/throttle utility library and unit-test the event-loop timing.