PostgreSQL and ActiveRecord have a good support for storing dynamic attributes (hashes) in columns of type JSONB. But sometimes you...

The sprintf method has a reference by name format option: sprintf("% d : % f", { :foo => 1, :bar => 2 }) # => 1 : 2.000000

Chromedriver (or selenium-webdriver?) will not reliably scroll elements into view before clicking them, and actually not click the element...

As an application exists, data accumulates. While you'll be loosely monitoring the main models' record count, some supportive database...

...calls html_safe if you're not escaping. FWIW, an HTML string may easily become invalid when truncated, e.g. when a closing tag gets chopped off. However, when the input...

If you use a newer SSH key generated with the ED25519 algorithm instead of RSA (see Create a new SSH...

Zeitwerk is the new autoloader of Rails. It is mandatory starting with Rails 7.0. Sometimes, a model needs to know...

When you have many changes, and you want to spread them across different commits, here is a way to stage...

Controllers Take care when defining nested resources, as they don't behave identical to namespaced resources: namespace :users do resources :sign_ups, only: [:new] end # GET /users/sign_ups/new...

...in controllers/sign_ups_controller.rb in order to make the second example work. You can alter this behaviour with a custom controller path, as shown in the very first example of this card...

When making cross-domain AJAX requests with jQuery (using CORS or xdomain or similar), you will run into issues with...

sudo gem install gettext --no-ri --no-rdoc sudo gem install fast_gettext --no-ri --no-rdoc script/plugin install git://...

Rails comes with grouped_collection_select that appears to be useful, but isn't. As an alternative, consider the flat...

CoffeeScript and JavaScript (ECMAScript) both have operators in and of. Each language use them for more than one purpose. There...

Two weeks ago, Cloudflare was struck by a global outage that lasted ~30 minutes. The incident was rooted on a...

If you migrate a Rails application from Sprockets to Webpack(er), you can either transpile your CoffeeScript files to JavaScript...

If you use transactional_fixtures or the database_cleaner gem with strategy :transaction, after_commit callbacks will not be fired...

...polymorphic association. class Event < ApplicationRecord has_many :letters, as: :record end class Letter < ApplicationRecord belongs_to :record, polymorphic: true end event = Event.new.letters.build event.save! # => ActiveRecord::RecordInvalid: Validation failed: Record must exist...

...member', :home_page end It has some limitations: Only works for singular member references ("belongs to"), not for a collection of references ("has many") No support for deletion (but could...

...when you run a Selenium test with Capybara. This will help you understand "impossible" behavior of your tests. When you run a Rack::Test (non-Javascript) test with Capybara, there...

...you. But sometimes the complexity will bleed through, causing your tests to show "impossible" behavior. Here is some unexpected behavior caused by the interaction of threads and processes:

...skipping asset compilation when assets have not changed? Turns out there is an even better way to speed up Capistrano deployments with asset compilation – and it's even simpler.

Carrierwave includes some handy helper methods you can use to resize your images. Here is a quick summary of them...

With cd .. you can navigate one directory up from the one you are at now. If you use that a...

# Capitalized expressions are intended to be replaced with YOUR values describe 'SERVICE', -> beforeEach -> module 'MODULE' module ($urlRouterProvider) -> # Prevent uiRouter's initialization, i.e. do not sync the current URL...