Leanpub Header

Skip to main content
Go to Leanpub.comLeanpub

Understanding JavaScript Promises

Nicholas C. Zakas

Learn all about JavaScript promises from veteran JavaScript author Nicholas C. Zakas.

The author is letting you choose the price you pay for this book!

Pick Your Price...
PDF
EPUB
WEB
404
Readers
107
Pages
19,315Words
About

About

About the Book

Since promises were added to JavaScript in 2015, they have become an integral part of the language. A good understanding of how promises work is more important than ever in becoming a proficient JavaScript developer. This book is written to introduce the promises and their intricacies in a straightforward, easy to read format. Each chapter is filled with practical, real-world examples using the techniques discussed, and all examples are available for download with your purchase.

What you'll learn:

  • Which parts of promises are synchronous and which are asynchronous
  • How to effectively use promise chains to simplify your code
  • The best way to catch errors in promises
  • How to create your own promises
  • Ways to work with multiple promises at once
  • How async functions and await expression hide promise complexities
  • How to abort asynchronous functions and create your own abortable functions
  • What happens to rejected promises without rejection handlers

Not ready to buy yet? Download a free preview first.

Share this book

Categories

JavaScript

Feedback

Email the author

Price

Pick Your Price...

Minimum price

$9.99

$14.99

You pay

$14.99

Author earns

$11.99
$

All prices are in US $. You can pay in US $ or in your local currency when you check out.

EU customers: prices exclude VAT, which is added during checkout.

...Or Buy With Credits!

Number of credits (Minimum 1)

1
The author will earn $12.00 from your purchase!
You can get credits monthly with a Reader Membership

Author

About the Author

Nicholas C. Zakas

Nicholas C. Zakas is an independent software engineer, consultant, coach, and has authored over a dozen books. He created the ESLint open source project and has worked on everything from small websites to massive-scale web applications. He has worked at Box as a principal architect and Yahoo as a presentation architect. Nicholas is a strong advocate for development best practices including progressive enhancement, accessibility, performance, scalability, and maintainability.

Translations

Translations

Languages

Contents

Table of Contents

Introduction

  1. About This Book
  2. Acknowledgments
  3. About the Author
  4. Disclaimer

1. Promise Basics

  1. The Promise Lifecycle
  2. Creating New (Unsettled) Promises
  3. Creating Settled Promises
  4. Summary

2. Chaining Promises

  1. Catching Errors
  2. Using finally() in Promise Chains
  3. Returning Values in Promise Chains
  4. Returning Promises in Promise Chains
  5. Summary

3. Working with Multiple Promises

  1. The Promise.all() Method
  2. The Promise.allSettled() Method
  3. The Promise.any() Method
  4. The Promise.race() Method
  5. Summary

4. Async Functions and Await Expressions

  1. Defining Async Functions
  2. What Makes Async Functions Different
  3. Summary

5. Abortable Functions

  1. Using an AbortController Object
  2. Custom Signals with AbortSignal
  3. Creating Abortable Functions
  4. Summary

6. Unhandled Rejection Tracking

  1. Detecting Unhandled Rejections
  2. Web Browser Unhandled Rejection Tracking
  3. Node.js Unhandled Rejection Tracking
  4. Summary

Final Thoughts

  1. Download the Extras
  2. Help and Support
  3. Follow the Author

The Leanpub 60 Day 100% Happiness Guarantee

Within 60 days of purchase you can get a 100% refund on any Leanpub purchase, in two clicks.

Now, this is technically risky for us, since you'll have the book or course files either way. But we're so confident in our products and services, and in our authors and readers, that we're happy to offer a full money back guarantee for everything we sell.

You can only find out how good something is by trying it, and because of our 100% money back guarantee there's literally no risk to do so!

So, there's no reason not to click the Add to Cart button, is there?

See full terms...

Earn $8 on a $10 Purchase, and $16 on a $20 Purchase

We pay 80% royalties on purchases of $7.99 or more, and 80% royalties minus a 50 cent flat fee on purchases between $0.99 and $7.98. You earn $8 on a $10 sale, and $16 on a $20 sale. So, if we sell 5000 non-refunded copies of your book for $20, you'll earn $80,000.

(Yes, some authors have already earned much more than that on Leanpub.)

In fact, authors have earned over $14 million writing, publishing and selling on Leanpub.

Learn more about writing on Leanpub

Free Updates. DRM Free.

If you buy a Leanpub book, you get free updates for as long as the author updates the book! Many authors use Leanpub to publish their books in-progress, while they are writing them. All readers get free updates, regardless of when they bought the book or how much they paid (including free).

Most Leanpub books are available in PDF (for computers) and EPUB (for phones, tablets and Kindle). The formats that a book includes are shown at the top right corner of this page.

Finally, Leanpub books don't have any DRM copy-protection nonsense, so you can easily read them on any supported device.

Learn more about Leanpub's ebook formats and where to read them

Write and Publish on Leanpub

You can use Leanpub to easily write, publish and sell in-progress and completed ebooks and online courses!

Leanpub is a powerful platform for serious authors, combining a simple, elegant writing and publishing workflow with a store focused on selling in-progress ebooks.

Leanpub is a magical typewriter for authors: just write in plain text, and to publish your ebook, just click a button. (Or, if you are producing your ebook your own way, you can even upload your own PDF and/or EPUB files and then publish with one click!) It really is that easy.

Learn more about writing on Leanpub