Unwrapping Monads & Friends
Unwrapping Monads & Friends
Shining Light on Functional Programming's Scariest Concepts
About the Book
Unwrapping Monads & Friends is a deep-yet-friendly guide to one of functional programming’s most notoriously misunderstood topics: the monad. Written with clarity, empathy, and a healthy dose of pragmatism, this book breaks through the fog of intimidating jargon and dense formalism to offer a clear, grounded understanding of what monads actually are—how they work, why they matter, and how they can improve the way we write and think about code.
This isn’t just "yet another monad tutorial." It’s a practical journey through the conceptual landscape of monads and their closely related "friends"—including functors, foldables, and applicatives—anchored in real JavaScript examples and a gradual learning curve. Whether you’ve struggled through Haskell-heavy blog posts or are just FP-curious, this guide offers a fresh path forward, revealing the power and elegance of these patterns without requiring a math degree or prior exposure to category theory.
Brought to you by Kyle Simpson, author of Functional-Light JavaScript and the You Don’t Know JS series (2 editions), this guide distills years of learning, teaching, and practical application into a concise and illuminating read. It’s ideal for anyone who’s FP-aware and ready to go deeper—especially those who’ve bounced off monads before and are ready to finally see what all the fuss is about.
Team Discounts
Get a team discount on this book!
Table of Contents
- Intro
-
Chapter 1: FP primer
- From Loop To Map And Filter
- Where To Learn More FP?
- How Do I Know…?
-
Chapter 2: What is a monad?
- What Is Monad?
- Simplest JS Illustration
- Building Up Monads
- Monadic Chain
- Back To The Core Of Monad
-
Chapter 3: Monads illustrated
- Maybe Something More?
- Reader Monad
-
State
fully Monadic
-
Chapter 4: I know IO (monad)!
- I/O with IO
- Non-Value-Container?
- But Why IO?
- Monad Summary
-
Chapter 5: Friends of monads
- Foldable
- Concatable (Semigroup)
- Applicative
- Wrapping up!
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 earnedover $14 millionwriting, 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