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)

FileSystem APIs

In the previous section, we learned about the global variables available to us in the Node.js execution context. In this section, we will learn about the FileSystem APIs, which are the APIs that are used to access files and directories, read and write data to files, and much more.

But before we dig into the FileSystem APIs, we need to understand streams. In Node.js, a Stream is an abstract interface that represents streaming data. In the previous section, we used the standard I/O and briefly mentioned that they are streams, so let's understand them in detail.

Streams can be readable, writable, or both. They are event emitters, which means that to receive data, you need to register event listeners, just like we did with standard input in the previous section:

process.stdin.addListener('data', (data) => {

In the next section, we will continue to build on our understanding of the previous sections and see that streams are...