briancolfer
Agile Web Development with Rails 7: Iteration E2 the add_product method
The add_product method assumes that the default value for the quantity attribute is 0 when it is nil.
I think the code example for add_product:
def add_product(product)
current_item = line_items.find_by(product_id: product.id)
if current_item
current_item.quantity += 1
else
current_item = line_items.build(product_id: product.id)
end
current_item
end
Should be:
def add_product(product)
# replace multiple items for a single product in a cart with a
# single item
current_item = line_items.find_by(product_id: product.id)
if current_item
if current_item.quantity.nil?
current_item.quantity = 1
else
current_item.quantity += 1
end
else
current_item = line_items.build(product_id: product.id, quantity: 1)
end
current_item
end
Marked As Solved
briancolfer
I forgot the default value in the migration.
Popular Pragmatic Bookshelf topics
page 37
ANTLRInputStream input = new ANTLRInputStream(is);
as of ANTLR 4 .8 should be:
CharStream stream = CharStreams.fromStream(i...
New
Title: Web Development with Clojure, Third Edition, pg 116
Hi - I just started chapter 5 and I am stuck on page 116 while trying to star...
New
Hi everyone!
There is an error on the page 71 in the book “Programming machine learning from coding to depp learning” P. Perrotta. You c...
New
Hello! On page xix of the preface, it says there is a community forum "… for help if your’re stuck on one of the exercises in this book… ...
New
I can’t setup the Rails source code. This happens in a working directory containing multiple (postgres) Rails apps.
With:
ruby-3.0.0
s...
New
The generated iex result below should list products instead of product for the metadata. (page 67)
iex> product = %Product{}
%Pento....
New
Title: Web Development with Clojure, Third Edition, vB17.0 (p9)
The create table guestbook syntax suggested doesn’t seem to be accepted ...
New
I’m under the impression that when the reader gets to page 136 (“View Data with the Database Inspector”), the code SHOULD be able to buil...
New
When I run the coverage example to report on missing lines, I get:
pytest --cov=cards --report=term-missing ch7
ERROR: usage: pytest [op...
New
Hello faithful readers! If you have tried to follow along in the book, you are asked to start up the dev environment via dx/build and ar...
New
Other popular topics
Which, if any, games do you play? On what platform?
I just bought (and completed) Minecraft Dungeons for my Nintendo Switch. Other than ...
New
No chair. I have a standing desk.
This post was split into a dedicated thread from our thread about chairs :slight_smile:
New
poll
poll
Be sure to check out @Dusty’s article posted here: An Introduction to Alternative Keyboard Layouts It’s one of the best write-...
New
Do the test and post your score :nerd_face:
:keyboard:
If possible, please add info such as the keyboard you’re using, the layout (Qw...
New
Saw this on TikTok of all places! :lol:
Anyone heard of them before?
Lite:
New
If you get Can't find emacs in your PATH when trying to install Doom Emacs on your Mac you… just… need to install Emacs first! :lol:
bre...
New
Author Spotlight
Mike Riley
@mriley
This month, we turn the spotlight on Mike Riley, author of Portable Python Projects. Mike’s book ...
New
Inside our android webview app, we are trying to paste the copied content from another app eg (notes) using navigator.clipboard.readtext ...
New
Hello,
I’m a beginner in Android development and I’m facing an issue with my project setup. In my build.gradle.kts file, I have the foll...
New
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...
New
Latest in Agile Web Development with Rails 7
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /wasm
- /ruby
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /clojure
- /emacs
- /java
- /haskell
- /svelte
- /onivim
- /typescript
- /kotlin
- /c-plus-plus
- /crystal
- /tailwind
- /react
- /gleam
- /ocaml
- /flutter
- /elm
- /vscode
- /ash
- /html
- /opensuse
- /zig
- /centos
- /deepseek
- /php
- /scala
- /lisp
- /react-native
- /sublime-text
- /textmate
- /nixos
- /debian
- /agda
- /django
- /kubuntu
- /deno
- /arch-linux
- /nodejs
- /ubuntu
- /revery
- /manjaro
- /spring
- /diversity
- /lua
- /julia
- /markdown
- /slackware








