Book Image

Professional JavaScript

By : Hugo Di Francesco, Siyuan Gao, Vinicius Isola, Philip Kirkbride
Book Image

Professional JavaScript

By: Hugo Di Francesco, Siyuan Gao, Vinicius Isola, Philip Kirkbride

Overview of this book

In depth knowledge of JavaScript makes it easier to learn a variety of other frameworks, including React, Angular, and related tools and libraries. This book is designed to help you cover the core JavaScript concepts you need to build modern applications. You'll start by learning how to represent an HTML document in the Document Object Model (DOM). Then, you'll combine your knowledge of the DOM and Node.js to create a web scraper for practical situations. As you read through further lessons, you'll create a Node.js-based RESTful API using the Express library for Node.js. You'll also understand how modular designs can be used for better reusability and collaboration with multiple developers on a single project. Later lessons will guide you through building unit tests, which ensure that the core functionality of your program is not affected over time. The book will also demonstrate how constructors, async/await, and events can load your applications quickly and efficiently. Finally, you'll gain useful insights into functional programming concepts such as immutability, pure functions, and higher-order functions. By the end of this book, you'll have the skills you need to tackle any real-world JavaScript development problem using a modern JavaScript approach, both for the client and server sides.
Table of Contents (12 chapters)

Symbols, Iterators, Generators, and Proxies

In JavaScript development, these types are rarely used, but for some use cases, they can be very useful. In this section, we will go over what these are and how we can use them in our applications.


Symbols are unique values; they can be used as an identifier because every time you call Symbol(), it returns a unique symbol. Even the function returns a Symbol type. However, it cannot be called using the new keyword because it is not a constructor. When stored in objects, they are not included when you iterate through the property list, so if you want to store anything as a property inside the object and do not want them to be exposed when you run JSON.stringify, you can use Symbols to achieve that.

Iterator and Generator

Iterator and Generator are often used together. Generator functions are functions whose code is not executed immediately when invoked. When a value is to be returned from the generator, it needs to be called...