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)

3. Node.js APIs and Web Scraping

Activity 4 Scraping Products and Prices from Storefront


  1. Start the dynamic server to serve the storefront application using the code from Exercise 14, Serving Dynamic Content, in this chapter:
    $ node Lesson03/Activity04/
    Static resources from /path/to/repo/Lesson03/Activity04/static
    Loaded 21 products...
    Go to: http://localhost:3000
  2. In a new Terminal, create a new npm package, install jsdom, and create the index.js entry file:
    $ npm init
    $ npm install jsdom
    + [email protected]
    added 97 packages from 126 contributors and audited 140 packages in 12.278s
    found 0 vulnerabilities
  3. Call the require() method to load all the modules you will need in the project:
    const fs = require('fs');
    const http = require('http');
    const JSDOM = require('jsdom').JSDOM;
  4. Make an HTTP request to http://localhost:3000:
    const page = 'http://localhost:3000';
    console.log(`Downloading ${page}...`);
    const request = http...