Kirjahaku

If you're like most developers, you rely heavily on JavaScript to build interactive and quick-responding web applications. The problem is that all of those lines of JavaScript code can slow down your apps. This book reveals techniques and strategies to help you eliminate performance bottlenecks during development. You'll learn how to improve execution time, downloading, interaction with the DOM, page life cycle, and more. Yahoo! frontend engineer Nicholas C. Zakas and five other JavaScript experts -- Ross Harmes, Julien Lecomte, Steven Levithan, Stoyan Stefanov, and Matt Sweeney -- demonstrate optimal ways to load code onto a page, and offer programming tips to help your JavaScript run as efficiently and quickly as possible. You'll learn the best practices to build and deploy your files to a production environment, and tools that can help you find problems once your site goes live. * Identify problem code and use faster alternatives to accomplish the same task * Improve scripts by learning how JavaScript stores and accesses data * Implement JavaScript code so that it doesn't slow down interaction with the DOM * Use optimization techniques to improve runtime performance * Learn ways to ensure the UI is responsive at all times * Achieve faster client-server communication * Use a build system to minify files, and HTTP compression to deliver them to the browser

Since promises were added to JavaScript in 2015, they have become an integral part of the language. A good understanding of how promises work is more important than ever in becoming a proficient JavaScript developer. This book begins by explaining the basic concepts behind promises, including what they are, how to use them, and how to create your own. You'll then build upon these basic concepts to learn how to chain promises together and how to respond to multiple promises at once. Once you've learned these advanced concepts, you'll move on to learn how promises work with async functions and how to track unhandled promise rejections. All of the concepts discussed are grounded in real world examples so you learn not just how to use a particular technique, but also why and when to use it. It doesn't matter if you're writing JavaScript for web browsers, Node.js, or Deno, this book will teach you everything you need to know about promises.