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)

Functions – First-Class Citizens

Functions being first-class means they are considered by the language to be like any other "value" type. This means that, in JavaScript, a function can be used just like a number, a string, a Boolean, an array, an object, and so on.


Now would probably be a good time to see how well-versed in JavaScript data types everyone is. The primitives are Boolean, Null, Undefined, Number, (BigInt), String, Symbol, Object à Array/Set/Map. They can be found under the Object data type.

First-Class Functions – Idiomatic JavaScript Building Blocks

Another way to define first-class support is as "functions are first-class if they are regular values." That means that a function can be assigned (as a value) to a variable, passed into other functions as a parameter, and be the return value of another function. Let's try and understand the preceding concept with code examples.

A function can be assigned to...