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)

ES6 Modules

When writing JavaScript with Node.js, the ability to import modules using the built-in require() function has long been used. As this feature was useful, many frontend developers began making use of it by pre-processing their JavaScript with compilers such as Babel. A JavaScript pre-compiler processes code that normally wouldn't work on most browsers and generates a new JavaScript file that is compatible.

As there was a large demand for an import style function in JavaScript, it was eventually added to the language in the ES6 version. At the time of writing, the latest version of most browsers is almost completely ES6 compatible. Yet the use of import can't be taken for granted, as many devices will continue to run older versions for years.

The rapid standardization of ES6 shows us that, going forward, ES6 imports will be the most popular method.

In the last chapter, we made use of the Node.js require method for importing a module. For example, take this...