jdsutherland
Modern Front-End Development for Rails: B7 pg 164 server JSON ids are numbers causing javascript Array#includes to always return false
After completing the section Using Data in Stimulus (ends pg 167), I noticed something wrong with Ajax updates. After running the rake task to sell out concerts, things looked fine on initial browser load:
but after Ajax it would change from “Sold Out” to “0 Tickets Remaining”:
The data attributes looked like this:
So concertSoldOutValue was suspiciously being set to false. The issue is that Array#includes is called with a string on an array of numbers (always false):
concertElement.dataset.concertSoldOutValue = soldOutConcertIds.includes(
concertElement.dataset.concertIdValue
)
typeof soldOutConcertIds[0]: number
The ids coming from the server JSON are numbers. One solution is to convert the ids to a string:
class SoldOutConcertsController < ApplicationController
def show
concerts = Concert.includes(:venue, gigs: :band).all
sold_out_concert_ids = concerts
.select(&:sold_out?)
.map(&:id)
.map(&:to_s)
render(json: {sold_out_concert_ids: sold_out_concert_ids})
end
end
Perhaps TypeScript could be leveraged to prevent this kind of bug?
First Post!
noelrappin
Author of Modern Front-End Development for Rails
This is a really great catch, I’ll fix it in the next update.
Popular Pragmatic Bookshelf topics
As per the title, thanks.
New
When I try the command to create a pair of migration files I get an error.
user=> (create-migration "guestbook")
Execution error (Ill...
New
Hi Jamis,
I think there’s an issue with a test on chapter 6. I own the ebook, version P1.0 Feb. 2019.
This test doesn’t pass for me:
...
New
Hi,
build fails on:
bracket-lib = “~0.8.1”
when running on Mac Mini M1 Rust version 1.5.0:
Compiling winit v0.22.2
error[E0308]: mi...
New
A Common-Sense Guide to Data Structures and Algorithms, Second Edition by Jay Wengrow @jaywengrow
Hi,
I have the paperback version of t...
New
When trying to generate the protobuf .go file, I receive this error:
Unknown flag: --go_opt
libprotoc 3.12.3
MacOS 11.3.1
Googling ...
New
This is as much a suggestion as a question, as a note for others.
Locally the SGP30 wasn’t available, so I ordered a SGP40. On page 53, ...
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 installing Cards as an editable package, I get the following error:
ERROR: File “setup.py” not found. Directory cannot be installe...
New
AWDWR 7, page 152, page 153:
Hello everyone,
I’m a little bit lost on the hotwire part. I didn’t fully understand it.
On page 152 @rub...
New
Other popular topics
Hello Devtalk World!
Please let us know a little about who you are and where you’re from :nerd_face:
New
Reading something? Working on something? Planning something? Changing jobs even!?
If you’re up for sharing, please let us know what you’...
New
Algorithms and data structures are much more than abstract concepts. Mastering them enables you to write code that runs faster and more e...
New
Andy and Dave wrote this influential, classic book to help their clients create better software and rediscover the joy of coding. Almost ...
New
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
We have a thread about the keyboards we have, but what about nice keyboards we come across that we want? If you have seen any that look n...
New
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
If you’re getting errors like this:
psql: error: connection to server on socket “/tmp/.s.PGSQL.5432” failed: No such file or directory ...
New
Curious what kind of results others are getting, I think actually prefer the 7B model to the 32B model, not only is it faster but the qua...
New
Background
Lately I am in a quest to find a good quality TTS ai generation tool to run locally in order to create audio for some videos I...
New
Latest in Modern Front-End Development for Rails
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /wasm
- /ruby
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /clojure
- /java
- /emacs
- /haskell
- /svelte
- /onivim
- /typescript
- /kotlin
- /c-plus-plus
- /crystal
- /tailwind
- /react
- /gleam
- /ocaml
- /elm
- /flutter
- /vscode
- /ash
- /html
- /opensuse
- /zig
- /deepseek
- /centos
- /php
- /scala
- /react-native
- /lisp
- /sublime-text
- /textmate
- /nixos
- /debian
- /agda
- /django
- /deno
- /kubuntu
- /arch-linux
- /nodejs
- /spring
- /ubuntu
- /revery
- /manjaro
- /julia
- /lua
- /diversity
- /markdown
- /quarkus











