briancolfer

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

briancolfer

I forgot the default value in the migration.

Where Next?

Popular Pragmatic Bookshelf topics Top

jimmykiang
This test is broken right out of the box… — FAIL: TestAgent (7.82s) agent_test.go:77: Error Trace: agent_test.go:77 agent_test.go:...
New
JohnS
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
joepstender
The generated iex result below should list products instead of product for the metadata. (page 67) iex> product = %Product{} %Pento....
New
leonW
I ran this command after installing the sample application: $ cards add do something --owner Brian And got a file not found error: Fil...
New
curtosis
Running mix deps.get in the sensor_hub directory fails with the following error: ** (Mix) No SSH public keys found in ~/.ssh. An ssh aut...
New
brunogirin
When trying to run tox in parallel as explained on page 151, I got the following error: tox: error: argument -p/–parallel: expected one...
New
adamwoolhether
Is there any place where we can discuss the solutions to some of the exercises? I can figure most of them out, but am having trouble with...
New
akraut
The markup used to display the uploaded image results in a Phoenix.LiveView.HTMLTokenizer.ParseError error. lib/pento_web/live/product_l...
New
a.zampa
@mfazio23 I’m following the indications of the book and arriver ad chapter 10, but the app cannot be compiled due to an error in the Bas...
New
gorkaio
root_layout: {PentoWeb.LayoutView, :root}, This results in the following following error: no “root” html template defined for PentoWeb...
New

Other popular topics Top

PragmaticBookshelf
Learn from the award-winning programming series that inspired the Elixir language, and go on a step-by-step journey through the most impo...
New
dasdom
No chair. I have a standing desk. This post was split into a dedicated thread from our thread about chairs :slight_smile:
New
PragmaticBookshelf
Design and develop sophisticated 2D games that are as much fun to make as they are to play. From particle effects and pathfinding to soci...
New
DevotionGeo
I know that -t flag is used along with -i flag for getting an interactive shell. But I cannot digest what the man page for docker run com...
New
PragmaticBookshelf
From finance to artificial intelligence, genetic algorithms are a powerful tool with a wide array of applications. But you don't need an ...
New
PragmaticBookshelf
Create efficient, elegant software tests in pytest, Python's most powerful testing framework. Brian Okken @brianokken Edited by Kat...
New
PragmaticBookshelf
Use WebRTC to build web applications that stream media and data in real time directly from one user to another, all in the browser. ...
New
AstonJ
If you want a quick and easy way to block any website on your Mac using Little Snitch simply… File > New Rule: And select Deny, O...
New
First poster: AstonJ
Jan | Rethink the Computer. Jan turns your computer into an AI machine by running LLMs locally on your computer. It’s a privacy-focus, l...
New
AstonJ
This is cool! DEEPSEEK-V3 ON M4 MAC: BLAZING FAST INFERENCE ON APPLE SILICON We just witnessed something incredible: the largest open-s...
New

Latest in Agile Web Development with Rails 7

Agile Web Development with Rails 7 Portal

Sub Categories: