Tutorial

Class syntax, constructors, methods, private fields, static members and extends.

How this is decided at call time, in methods, callbacks, arrow functions and with bind, call and apply.

Transform and search arrays with built-in methods, chaining, and which methods mutate.

Unpack arrays and objects, copy and merge with spread, and collect arguments with rest.

Object.keys, values and entries, shallow versus deep copies with structuredClone, and Object.freeze.

Repeat work with each loop type, break and continue, and which loop suits arrays and objects.

Define and call functions, default parameters, return values and function expressions.

Arrow function syntax, implicit returns, and how arrows differ from regular functions.

Create arrays, read and change elements, add and remove items, and check length.

Create objects, read and update properties, methods, and bracket notation for dynamic keys.

What the DOM is, and selecting elements with querySelector, querySelectorAll and getElementById.

Update text, attributes, classes and styles safely, and why textContent beats innerHTML for user data.

Listen for clicks, input and keyboard events, the event object, and preventDefault.

What JavaScript does in the browser and on servers, how it relates to HTML and CSS, and what ECMAScript means.

Read form values, handle submit, give live validation feedback and send data without a page reload.

Run code in the browser console, load scripts with the script element and defer, and run files with Node.js.

Declare variables with let and const, why var is avoided, and naming conventions.

Primitive types, objects, null versus undefined, and checking types with typeof.