PragProg Customers

Practical Microservices: Missing expected version in recordViewing function (page 37)

nicholasjhenry

nicholasjhenry

Practical Microservices: Missing expected version in recordViewing function (page 37)

The function call for the message store is:

// video-tutorials/src/app/record-viewings/index.js
messageStore.write(streamName, viewedEvent)

but the function def is:

// video-tutorials/src/message-store/write.js
return (streamName, message, expectedVersion) => {
 // implementation
}

Is there something I missing?

1 comment
#errata/book-practical-microservices
3 832 1

Marked As Solved

nicholasjhenry

nicholasjhenry

Perhaps a lack in my knowledge of JavaScript and Message DB. Calling the function with the first two parameters will result in expectedVersion to be null. If write_message is invoked with a null then no version check is made. I can see how this behaviour would be desired for logging events compared to managing the state of an aggregate (DDD) where the expected version is important.

2
Post #2

Where Next?

View thread on forum
View Practical Microservices's book portal
Post errata for this book
Post a suggestion for this book
Post a question about this book
Post a review about this book
Home PragProg Customers
#errata/book-practical-microservices
3 832 1
Last post

Popular Pragmatic Bookshelf topics Top

brianokken
PragProg Customers

Python Testing with pytest: pytest now requires markers to be declared (downloadable code)
Many tasks_proj/tests directories exist in chapters 2, 3, 5 that have tests that use the custom markers smoke and get, which are not decl...
#errata/book-python-testing-with-pytest
2 1383 2
New
herminiotorres
PragProg Customers

Programming Phoenix LiveView: Typo
Hi! I know not the intentions behind this narrative when called, on page XI: mount() |> handle_event() |> render() but the correc...
#errata/book-programming-phoenix-liveview
3 1307 17
New
patoncrispy
PragProg Customers

Hands-on Rust: Adequate docs for bracket_lib
I’m new to Rust and am using this book to learn more as well as to feed my interest in game dev. I’ve just finished the flappy dragon exa...
#question/book-hands-on-rust
5 1516 3
New
AndyDavis3416
PragProg Customers

Modern Front-End Development for Rails: ERROR in tsconfig.json Chapter_01/01
@noelrappin Running the webpack dev server, I receive the following warning: ERROR in tsconfig.json TS18003: No inputs were found in c...
/book-modern-front-end-development-for-rails
3 1438 3
New
Charles
PragProg Customers

Programming Phoenix LiveView: book not updated to version 1.6 (p. 18)
In general, the book isn’t yet updated for Phoenix version 1.6. On page 18 of the book, the authors indicate that an auto generated of ro...
#errata/book-programming-phoenix-liveview
9 2051 12
New
kevinjyh
PragProg Customers

Python Testing with pytest, Second Edition:Abou epub format
Is the book’s epub format available to read on Google Play Books?
#question/book-python-testing-with-pytest-second-edition
0 1126 3
New
hazardco
PragProg Customers

Agile Web Development with Rails 7: Example code does not work delete method (page 78)
On page 78 the following code appears: <%= link_to ‘Destroy’, product, class: ‘hover:underline’, method: :delete, data: { confirm...
#suggestion/book-agile-web-development-with-rails-7
1 1266 2
New
s2k
PragProg Customers

Agile Web Development with Rails 7: Reloading assets in development mode
Hi all, currently I wonder how the Tailwind colours work (or don’t work). For example, in app/views/layouts/application.html.erb I have...
#question/book-agile-web-development-with-rails-7
2 1380 4
New
redconfetti
PragProg Customers

Docker for Rails Developers - 'docker-machine' command deprecated (page 156)
Docker-Machine became part of the Docker Toolbox, which was deprecated in 2020, long after Docker Desktop supported Docker Engine nativel...
/book-docker-for-rails-developers#suggestion
0 896 0
New
SlowburnAZ
PragProg Customers

Machine Learning in Elixir:Error installing EXLA dependency - Page 25
Getting an error when installing the dependencies at the start of this chapter: could not compile dependency :exla, "mix compile" failed...
#errata/book-machine-learning-in-elixir
1 1159 10
New

Other popular topics Top

PragmaticBookshelf
Backend>Learning Resources

Web Development with Clojure, Third Edition
Stop developing web apps with yesterday’s tools. Today, developers are increasingly adopting Clojure as a web-development platform. See f...
pragprog.com
#pragprog#web-development/clojure#published-book/book-web-development-with-clojure-third-edition
5 4584 1
New
dasdom
General Dev>Dev Chat

Standing Desks
No chair. I have a standing desk. This post was split into a dedicated thread from our thread about chairs :slight_smile:
#workspace#opinions
177 9886 77
New
AstonJ
General Dev>Hardware

Custom keyboard keycaps
There’s a whole world of custom keycaps out there that I didn’t know existed! Check out all of our Keycaps threads here: https://forum....
#hardware/keyboards#keycaps#mechanical-keyboards
15 11086 19
New
Exadra37
Linux>Chat

RancherOS is in end of life
Oh just spent so much time on this to discover now that RancherOS is in end of life but Rancher is refusing to mark the Github repo as su...
#linux#rancheros
10 6358 6
New
foxtrottwist
General Dev>Dev Chat

Warp—The blazingly fast, Rust-based terminal
A few weeks ago I started using Warp a terminal written in rust. Though in it’s current state of development there are a few caveats (tab...
/rust#terminal
52 6785 22
New
PragmaticBookshelf
Backend>Learning Resources

Effective Haskell
Build efficient applications that exploit the unique benefits of a pure functional language, learning from an engineer who uses Haskell t...
pragprog.com
#pragprog/haskell#published-book/book-effective-haskell
15 10218 1
New
PragmaticBookshelf
Backend>Learning Resources

Ash Framework
Explore the power of Ash Framework by modeling and building the domain for a real-world web application. Rebecca Le @sevenseacat and ...
pragprog.com
#pragprog/elixir#published-book/ash/book-ash-framework
15 7555 9
New
AstonJ
AI>Chat

How to: Run DeepSeek on Mac, Windows, and Linux!
This is a very quick guide, you just need to: Download LM Studio: https://lmstudio.ai/ Click on search Type DeepSeek, then select the o...
#macs/deepseek#guides#lm-studio
14 9328 10
New
PragmaticBookshelf
Backend>Learning Resources

Advanced Functional Programming with Elixir
Use advanced functional programming principles, practical Domain-Driven Design techniques, and production-ready Elixir code to build scal...
joekoski.com
#pragprog/elixir#published-book#functional-programming/book-advanced-functional-programming-with-elixir
43 4989 22
New
xiji2646-netizen
AI>Chat

Claude Code's entire source just leaked (512K lines) - anyone else digging through it?
Woke up to this today: Claude Code’s complete source code exposed via npm source map. Not a snippet. All 512,000 lines. 1,900 TypeScript ...
#claude
1 5903 4
New
Back to top

Latest in Practical Microservices

Practical Microservices Portal ❯

PragProg Customers

Pragmatic Bookshelf PragProg Customers ❯

Latest on Devtalk

Devtalk ❯

We ❤️ helpful members!

We reward our most helpful members via our MOTM scheme - by giving away a whopping 25 books per year!

Member of the Month

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

Linux New Media

Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.

View all our sponsors ❯

Categories:

Sub Categories:

Popular Portals

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

Linux New Media

Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.

View all our sponsors ❯

We're in Beta

About us Mission Statement See our Roadmap