Book excerpt: JavaScript is a tool for the gurus who create highly useful applications, but it has some limitations. To overcome these limitations, a concept called JavaScript promises is rising rapidly in popularity. Promises makes writing complex logics more manageable and easy. This book starts with an introduction to JavaScript promises and how it has evolved over time. You will learn the JavaScript asynchronous model and how JavaScript handles asynchronous programming. Next, you will explore the promises paradigm and its advantages. Finally, this book will show you how to implement promises in platforms used in project development including WinRT, jQuery, and Node.js.