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)

The Traditional Approach versus Event-Driven Programming

As we mentioned in the introduction, in traditional programming patterns, we like to have a direct link between our components when we want them to communicate. This is shown in the following diagram:

Figure 9.1: Traditional programming approach

For a simple application that allows the user to update their profile and receive messages, we can see that we have four components:

  • Agent
  • Profile
  • Votes
  • Messages

The way these components interact with each other is by calling the appropriate methods in the component that wishes to communicate. By doing this, it makes the code very easy to understand, but we might have to pass the component reference over. Take our Agent class, for example:

class Agent {
    constructor(id, agentInfo, voteObj, messageObj) {
        this.voteObj = voteObj;