Java Script Programming Study Notes

Common Array Methods in JavaScript

Explore the most-used array methods, split into mutating methods that change the original array and non-mutating methods that return a new array.

Arrays in JavaScript

Understand how JavaScript arrays store ordered lists of values, how indexing and length work, and why `typeof` alone can't identify an array.

async/await in JavaScript

Learn how async/await provides synchronous-looking syntax for working with Promises, including error handling with try/catch.

break and continue in JavaScript

Learn how to alter loop execution with break and continue, and how labeled statements let you control outer loops from inside nested loops.

Callback Functions in JavaScript

Understand callback functions, the difference between synchronous and asynchronous callbacks, and the callback hell problem.

Callbacks and Asynchronous JavaScript

Learn how JavaScript handles operations that take time using callback functions, and why deeply nested callbacks lead to callback hell.

Classes in JavaScript

How ES6 class syntax provides a cleaner, structured way to create objects and implement object-oriented patterns on top of JavaScript's prototype system.

Closures in JavaScript

Understand how closures let inner functions remember and access variables from their outer scope, and how loop variable capture can trip you up.

Comments in JavaScript

Learn how to write single-line and multi-line comments in JavaScript to document and disable code.

Console and Debugging in JavaScript

Learn the core console methods and debugging techniques for inspecting and troubleshooting JavaScript code.

Constructors in JavaScript

How constructor functions and class constructors initialize new objects, run automatically with `new`, and support default parameters.

Custom Errors in JavaScript

Building your own Error subclasses by extending the built-in Error class to represent domain-specific failures.

Data Types in JavaScript

Understand JavaScript's primitive and reference data types and how the typeof operator identifies them.

Default and Rest Parameters in JavaScript

Use default parameter values and gather variable numbers of arguments with rest parameters.

Destructuring in JavaScript

Learn how to unpack values from arrays and properties from objects into distinct variables using destructuring, including defaults and renaming.

The DOM in JavaScript

Understand the Document Object Model — the live, tree-structured in-memory representation of a web page that JavaScript reads and modifies.

DOM Manipulation in JavaScript

Learn how to select, create, modify, and remove DOM elements using JavaScript, and the key differences between the main selector APIs.

Encapsulation in JavaScript

How JavaScript hides internal object state using ES2022 private class fields (`#field`) and the older underscore naming convention.

Error Handling in JavaScript

How JavaScript represents runtime failures with Error objects and the built-in TypeError, RangeError, ReferenceError, and SyntaxError types.

Event Bubbling and Capturing in JavaScript

Understand the two phases of DOM event propagation — capturing (top-down) and bubbling (bottom-up) — and how to control them.

Event Handling in JavaScript

Learn how to listen for and respond to user interactions and browser events using addEventListener and the event object.

The Event Loop in JavaScript

Understand the call stack, macrotask queue, and microtask queue, and master the ordering rules that govern async execution.

Features of JavaScript

A survey of JavaScript's core characteristics: dynamic typing, first-class functions, prototypal inheritance, and asynchronous support.

Fetch API in JavaScript

Use the Fetch API to make HTTP requests, and learn the critical gotcha that fetch does not reject on HTTP error status codes.