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Professional JavaScript

You're reading from   Professional JavaScript Fast-track your web development career using the powerful features of advanced JavaScript

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Product type Paperback
Published in Sep 2019
Publisher
ISBN-13 9781838820213
Length 664 pages
Edition 1st Edition
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Authors (4):
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Hugo Di Francesco Hugo Di Francesco
Author Profile Icon Hugo Di Francesco
Hugo Di Francesco
Siyuan Gao Siyuan Gao
Author Profile Icon Siyuan Gao
Siyuan Gao
Vinicius Isola Vinicius Isola
Author Profile Icon Vinicius Isola
Vinicius Isola
Philip Kirkbride Philip Kirkbride
Author Profile Icon Philip Kirkbride
Philip Kirkbride
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Toc

Table of Contents (12) Chapters Close

Preface 1. JavaScript, HTML, and the DOM 2. Node.js and npm FREE CHAPTER 3. Node.js APIs and Web Scraping 4. RESTful APIs with Node.js 5. Modular JavaScript 6. Code Quality 7. Advanced JavaScript 8. Asynchronous Programming 9. Event-Driven Programming and Built-In Modules 10. Functional Programming with JavaScript Appendix

1. JavaScript, HTML, and the DOM

Activity 1: Extracting Data from a Page

Solution:

  1. Initialize a variable to store the entire content of the CSV:
    var csv = 'name,price,unit\n';
  2. Query the DOM to find all the elements that represent each product. Notice how we wrap the HTMLCollection instance returned in Array.from so that we can handle it like a normal array:
    var elements = Array.from(document.getElementsByClassName('item'));
  3. Iterate over each element found:
    elements.forEach((el) => {});
  4. Inside the closure, using the product element, query to find the price with the unit. Split the string using a slash:
    var priceAndUnitElement = el.getElementsByTagName('span')[0];
    var priceAndUnit = priceAndUnitElement.textContent.split("/");
    var price = priceAndUnit[0].trim();
    var unit = priceAndUnit[1].trim();
  5. Then query for the name:
    var name = el.getElementsByTagName('a')[0].textContent;
  6. Append all information to the variable...
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