If you've ever felt the exhilaration of cracking a thorny problem or the joy of witnessing elegant code that challenges your mind, then this book is tailor-made for you. Prepare yourself to dive into a diverse array of mind-bending JavaScript brain teasers. Each puzzle is more than just a code exercise; it's a gateway to unlocking new insights and honing your abilities. As you work through the challenges, you'll learn to think pragmatically, optimize your code for efficiency, and avoid hidden pitfalls that can catch you off guard. What's more - the puzzle format will help you remember what you've learned! Over the years, JavaScript has gained a bit of a reputation for its quirky and unique characteristics. It's important for developers to be aware of these quirks to write more robust and predictable JavaScript code. In this book, we invite you on a journey designed to unveil the intricate nuances and peculiarities that define the language's essence. Learn how to simulate function overloading, embed hidden information within objects, develop self-contained functions capable of maintaining their own local state, generate number sequences using functional programming, handle exotic forms of IIFEs, and prevent loss of precision when dealing with large numbers. Grasp concepts like closures, hoisting, symbols, execution context, event queue, text normalization, and more, one puzzle at a time. Discover how to create your own custom objects that function as shortcuts, accurately calculate the length of emojis and Unicode characters, master the usage of the "this" keyword, leverage bitwise operators, and convert color names to hex notation for universal use across various platforms. Plus, steer clear of those usual traps and blunders that trip up JavaScript developers. Forget passive learning. With JavaScript Brain Teasers, you'll actively engage with code puzzles that require creative thinking and problem-solving, which help you memorize difficult concepts. What You Need: Certain code examples take advantage of recently introduced JavaScript features. Therefore, it's important to use a JavaScript environment that supports ECMAScript 2020 or a newer version. The simplest way to experiment with the examples is use your browser's console. Just make sure your browser is up-to-date.