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Hands-on JavaScript for Python Developers

You're reading from  Hands-on JavaScript for Python Developers

Product type Book
Published in Sep 2020
Publisher Packt
ISBN-13 9781838648121
Pages 410 pages
Edition 1st Edition
Author (1):
Sonyl Nagale Sonyl Nagale
Profile icon Sonyl Nagale

Table of Contents (26) Chapters

Preface 1. Section 1 - What is JavaScript? What is it not?
2. The Entrance of JavaScript into Mainstream Programming 3. Can We Use JavaScript Server-Side? Sure! 4. Nitty-Gritty Grammar 5. Data and Your Friend, JSON 6. Section 2 - Using JavaScript on the Front-End
7. Hello World! and Beyond: Your First Application 8. The Document Object Model (DOM) 9. Events, Event-Driven Design, and APIs 10. Working with Frameworks and Libraries 11. Deciphering Error Messages and Performance Leaks 12. JavaScript, Ruler of the Frontend 13. Section 3 - The Back-End: Node.js vs. Python
14. What Is Node.js? 15. Node.js versus Python 16. Using Express 17. React with Django 18. Combining Node.js with the Frontend 19. Enter Webpack 20. Section 4 - Communicating with Databases
21. Security and Keys 22. Node.js and MongoDB 23. Putting It All Together 24. Assessments 25. Other Books You May Enjoy

Accommodating JavaScript's performance limitations

As with any language, there are ways to write JavaScript and better ways to write it. What is not as obvious in other languages, however, is the direct implications of your code for the user experience of a website. Complicated, inefficient code can clog up a browser, eat CPU cycles, and, in some cases, even crash the browser.

Take a look at this simple four-line snippet by Talon Bragg from https://hackernoon.com/crashing-the-browser-7d540beb0478:

txt = "a";
while (1) {
txt = txt += "a"; // add as much as the browser can handle
}

Warning: do not attempt to run this in a browser! If you're curious about what this does, it will eventually create an out-of-memory exception in the browser that will kill the tab with a message that the page has become unresponsive. Why is this? Our while loop has a simple truthy value for its condition, so it will continue adding "a" to the string text until the memory...

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