JS

JavaScript

beginner

The language that runs the web. Whether you like it or not.

JavaScript is the only language that runs natively in every web browser. Originally written in 10 days. Somehow it took over the world. Now it runs on servers, mobile devices, and against all reason, your smart toaster.

Web FrontendBackend (Node.js)Mobile (React Native)Desktop (Electron)
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0/14 lessons

Setup

JavaScript runs in every browser, so you already have a runtime. For serious development, install Node.js to run JS outside the browser.

Bash
# Download Node.js from nodejs.org
# Get the LTS (Long Term Support) version

# Or use winget:
winget install OpenJS.NodeJS.LTS

# Verify:
node --version
npm --version

Lessons

1
Hello, World!
You can run JavaScript in your browser's console right now. Open DevTools (F12),…
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2
Variables & Types
JavaScript has three ways to declare variables: var, let, and const. One is old …
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3
Control Flow & Loops
JavaScript has all the standard control structures, plus a few extras. It's also…
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4
Functions & Arrow Functions
JavaScript has multiple syntaxes for functions. This is not a bug, it's a featur…
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5
Arrays & Objects
Arrays and objects are the backbone of JavaScript data. Master these and you've …
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6
Classes & Modules
ES6 brought classes to JavaScript. They're syntactic sugar over prototypes, but …
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7
Promises & Async/Await
JavaScript is single-threaded but non-blocking. This sounds impossible and makes…
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8
Mini Project: Fetch & Display Data
Let's build a real Node.js script that fetches data from a public API and displa…
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9
Closures & Scope
A closure is a function that remembers the variables from the scope it was creat…
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10
Destructuring, Spread & Rest
ES6 destructuring lets you unpack arrays and objects in a single expression. Com…
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11
DOM & Events
The DOM is the browser API that lets JavaScript interact with HTML. It is a tree…
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12
Modules & npm
JavaScript modules let you split code across files and import only what you need…
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13
Error Handling & Debugging
JavaScript has one Error type but many error names, a try/catch that silently sw…
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14
JavaScript Cheatsheet
Modern JS on one page — ES6+ syntax, arrays, async, DOM.
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