JavaScript

We explain what functional programming is, with five examples of how you can make your JavaScript more functional in style.

Learn what JavaScript callbacks are, how they work, their different types, how to create them, and how to employ them in your own code.

Learn how to avoid callback hell without ditching callbacks! By applying some SOLID principles, callbacks can still be a useful technique.

Learn how JavaScript promises work, how to create and chain them, how promise error handling works, and how to use recent promise methods.

Learn how to choose between React and Next.js, based on their popularity, documentation, performance, and the type of app you're building.

Our list of beginner JavaScript books will help you build the solid foundation you need for success.

Learn how to work with the new Google Auth by configuring a Sign in with Google button in a React.js and Express.js application.

Learn about the syntax of the ternary operator in JavaScript, some of its common uses, and when it's a good option to choose.

Learn the different ways you can use the spread operator in JavaScript, and the main difference between the spread and rest operators.

Explore some of the missing math methods in JavaScript — such as sum, product, factorial, odd and even — and how to write functions for them.

Learn what you can do with the built-in JavaScript Math object, which includes useful functions for performing mathematical operations.

In this quick JavaScript regex matching guide, you'll learn how to test if a string matches a regular expression using the test() method.

Learn how to use Math.random to generate random numbers in JavaScript and create random colors, letters, strings, phrases, passwords, & more.

Learn how to transform the character case of a string — to uppercase, lowercase, and title case — using native JavaScript methods.

Learn about methods for rounding numbers in JavaScript: rounding up, rounding down, rounding to decimal places, and gotchas to avoid.

Learn how to split a string into substrings in JavaScript with both the substring() and split() methods, and how to choose which one to use.

Learn how to convert numbers to ordinals in JavaScript. Getting the ordinal of a number allows you to display it in a human-readable format.

Learn three simple ways to convert a string into a number in JavaScript, with simple-to-follow examples and tips on which method to use.

Learn four simple ways to convert a number into a string in JavaScript, with simple-to-follow examples and tips on which method to use.

The REST API is a key part of web infrastructure. Learn about REST and REST APIs, and how web apps communicate over HTTP like web browsers and servers do.

In this TypeScript vs JavaScript comparison, you'll learn about TypeScript's advantages and disadvantages, and when and when not to use it.

Follow this tutorial to build your own Wordle alternative for numbers in JavaScript: Numble.

Nanny State helps you manage state simply and efficiently in JavaScript without Redux, Vuex or other large libraries

Learn about the browser's global object — the window object — which represents the browser window that contains a web page.

Learn about the most used and useful APIs built in to the standard Node.js runtime to save you time and improve your app's efficiency.

The best JavaScript charting libraries for creating and graphs and figures. From the scientific to the simple.

In this guide, we will show you how you can learn to code with JavaScript for free. The JavaScript programming language is versatile, popular, and in high demand — making it a great language for learning how to code.

Learning always takes more time than we'd like. If you’re learning JavaScript, these six mental tricks will help you get there faster.

Learn when to use function expressions vs. function declarations in JavaScript, and how these methods for defining functions are different.

Learn how to use JavaScript arrow functions, understand fat and concise arrow syntax, and what to be aware of when using them in your code.