JavaScript Fundamentals Tutorial
Learn JavaScript the practical way: types, functions, arrays, the DOM and async code
Beginner4 lessonsabout 21 min of reading
This course is for beginners who want to understand JavaScript rather than copy snippets: people learning web development, developers moving over from Python or Java, and anyone who has used a framework without ever learning the language underneath it. You need a browser and Node.js (any recent version) installed. Most examples are single files you run with node file.js; the DOM lesson uses a small HTML page you open in your browser.
Each lesson is anchored in its own scenario: a snack vending machine, a warehouse stock list, a theatre seat picker and a parcel-tracking service. By the end you will be able to declare variables with the right keyword, predict what an expression will evaluate to, transform data with map, filter and reduce, wire up page interactions with event listeners, and write asynchronous code with promises and async/await without the usual confusion about ordering.
The order matters. First the language core: values, types and functions. Then objects and arrays, which carry nearly all real data. Then the browser's DOM and events, where the language meets a page. Finally asynchronous JavaScript, which underpins every network call. After this course the natural next steps are TypeScript, React and Node.js.
JavaScript Fundamentals lessons
- 1JavaScript Variables, Data Types and Functions ExplainedLearn let, const and var, JavaScript's data types, type coercion, === versus ==, and how to write functions, arrow functions and closures with clear examples.5 min read
- 2JavaScript Objects, Arrays and Array Methods (map, filter, reduce)Work with JavaScript objects and arrays: destructuring, spread, map, filter, reduce, find, sort and the copy-versus-reference traps, using a stock list.5 min read
- 3JavaScript DOM and Events: Select, Update and Respond to ClicksLearn the JavaScript DOM: select and create elements, change text and classes, handle click and submit events, and use event delegation, with a seat picker.6 min read
- 4JavaScript Promises, async/await and fetch ExplainedUnderstand the JavaScript event loop, promises, async/await, Promise.all and fetch error handling, with a runnable parcel-tracking client and server in Node.5 min read
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