Book Image

ECMAScript Cookbook

By : Ross Harrison
Book Image

ECMAScript Cookbook

By: Ross Harrison

Overview of this book

ECMAScript Cookbook follows a modular approach with independent recipes covering different feature sets and specifications of ECMAScript to help you become an efficient programmer. This book starts off with organizing your JavaScript applications as well as delivering those applications to modem and legacy systems. You will get acquainted with features of ECMAScript 8 such as async, SharedArrayBuffers, and Atomic operations that enhance asynchronous and parallel operations. In addition to this, this book will introduce you to SharedArrayBuffers, which allow web workers to share data directly, and Atomic operations, which help coordinate behavior across the threads. You will also work with OOP and Collections, followed by new functions and methods on the built-in Object and Array types that make common operations more manageable and less error-prone. You will then see how to easily build more sophisticated and expressive program structures with classes and inheritance. In the end, we will cover Sets, Maps, and Symbols, which are the new types introduced in ECMAScript 6 to add new behaviors and allow you to create simple and powerful modules. By the end of the book, you will be able to produce more efficient, expressive, and simpler programs using the new features of ECMAScript. ?
Table of Contents (20 chapters)
Title Page
Copyright and Credits
Dedication
PacktPub.com
Contributors
Preface
Index

Introduction


In earlier versions of JavaScript, the callback pattern was the most common way to organize asynchronous code. It got the job done, but it didn't scale well. With callbacks, as more asynchronous functions are added, the code becomes more deeply nested, and it becomes more difficult to add to, refactor, and understand the code. This situation is commonly known as callback hell.

Promises were introduced to improve on this situation. Promises allow the relationships of asynchronous operations to be rearranged and organized with more freedom and flexibility.

The recipes in this chapter demonstrate how to use promises to create and organize asynchronous functions, as well as how to handle error conditions.