...or every even-numbered item. However, :nth-child can do more. In modern CSS specifications (Level 4), there’s an additional feature that lets you use :nth-child in combination...
...with a list of css selectors. This way, you can target the nth-child within a subset of siblings matching a selector. For example: .container .foo %span.my-selector .bar
...default order" of rows in database tables. For instance, when you paginate a result set: When using LIMIT, it is important to use an ORDER BY clause that constrains the...
...result rows into a unique order. Otherwise you will get an unpredictable subset of the query's rows. You might be asking for the tenth through twentieth rows, but tenth...
PostgreSQL's Common Table Expressions (CTEs) can be used to extract sub-queries from bulky SQL statements into a temporary table to be referenced instead. This is most useful to...
...avoid ugly joins or sub-selects. CTEs can be used for SELECT, INSERT, UPDATE or DELETE. Example (from the PostgreSQL docs): WITH regional_sales AS ( SELECT region, SUM(amount) AS...
...you prepare your changelist properly, it directs your reviewer’s attention to areas that support your growth rather than boring style violations. When you demonstrate an appreciation for constructive criticism...
...your reviewer provides better feedback . Make others better: Your code review techniques set an example for your colleagues. Effective author practices rub off on your teammates, which makes your job...
When you need to add a event listener to hundreds of elements, this might slow down the browser. An alternative is to register an event listener at the root of...
...for events to bubble up and check whether the triggering element (event.target) matches the selector before you run your callback. This technique is called event delegation. Performance considerations
Whenever you have to deal with randomness in a jasmine test there are some spy strategies to help you out! Let's say we have a method Random.shuffle(array) to...
...shuffle an array randomly and a class that uses shuffle within the constructor. returnValue & returnValues it('shuffles the array', () => { spyOn(Random, 'shuffle').and.returnValue([3, 2, 1])
Bundler so far ignored the version specified under BUNDLED_WITH in the Gemfile.lock. This had two annoying consequences: If the bundler version on your system was lower than in the...
...and had to manually install the correct version. If the bundler version on your system was higher than in the Gemfile.lock, bundler silently updated the version in the Gemfile.lock to...
Splitting up commits makes the process of reviewing often easier, since you can create several merge requests or review every commit one by one. So when you find out that...
...refactoring along the current changes, you can use one of the following processes to split up the changes into several commits in a logical order: #1 Splitting up the last...
You need to update a lof gems. Make sure you don't have any version constraints in your Gemfile or your bundle update won't do anything!
...cucumber_priority: bundle update cucumber_priority Upgrade spreewald: bundle update spreewald Upgrade cucumber_factory: bundle update cucumber_factory Upgrade parallel_tests: bundle update parallel_tests Even on the latest version...
I find it annoying to iterate on a spec that relies on a recorded VCR casette...
...You constantly have to remove the same YAMLs file before you can re-run that still-red test. With this little helper, you (or your coding agent) can do the...
...hints on best practices to maintain your tasks in larger projects. Rake Tasks vs. Scripts The Rails default is using rake tasks for your application tasks. These live in lib/tasks...
...case you want to avoid rake for your tasks and just use plain ruby scripts, consider lib/scripts/* as folder. Keeping tasks slim For readability and testing it's easier to...
YJIT is Ruby's default just-in-time compiler. It is considered production-ready since Ruby 3.2 (source). To activate YJIT you need two steps: Your ruby binary needs to...
...be compiled with YJIT support. You need to enable YJIT. Getting a Ruby with YJIT support We usually install Ruby with tools like rbenv or asdf. This compiles the ruby...
In long diffs, it can become impossible to spot small changes in larger blocks of moved code. This may be either a method that was moved from the top to...
...the bottom of a file, or a long test file that was split in many. Fortunately, Git offers a special highlighting mode that directs the reader's attention to relevant...
...and how to normalize them. In the example below, the Movie#title attribute is stripped from leading and trailing whitespace automatically: class Movie < ApplicationRecord normalizes :title, with: -> { _1.strip } end
...a class. Which could look like this: class Movie < ApplicationRecord normalizes :title, with: Normalizers::StripNormalizer end The with keyword accepts any callable object that takes the attribute’s value as...
When using Rails to truncate strings, you may end up with strings that are still too long for their container or are not as long as they could be. You...
...did not use it. Since Firefox 7 you can! Note that this only works for single-line texts. If you want to truncate tests across multiple lines, use a JavaScript...
...they reach approx. 100MB: $ ls -lh log/ -rw-r--r-- 1 user group 55M Sep 15 09:54 development.log -rw-r--r-- 1 user group 101M Aug...
...development.log.0 This behavior is a built-in feature of Ruby's standard Logger class, which Rails uses by default. To control the maximum file size, set config.log_file_size...
Most of the time, when you are interested in any log output, you see the logs directly on your console or you tail / grep some logfile in a separate terminal...
...In rare cases it's helpful to redirect the Logger output temporary to e.g. STDOUT. Rails.logger = Logger.new(STDOUT) ActiveRecord::Base.logger = Logger.new(STDOUT) User.save! #=> D, [2025-09-08T11...
Remember How to skip Sprockets asset compile during Capistrano deployment and Automatically 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. Adding the asset cache directory to symlinked directories Popular asset managers for Rails are Sprockets and Webpacker. Both keep...
Sometimes it's nice to have some coloring in your logs for better readability. You can output your logs via tail and pipe this through sed to add ANSI color...
...containing "FATAL" in red and all lines with "INFO" in green: tail -f /path/to/log | sed --unbuffered -e 's/\(.*INFO.*\)/\o033[32m\1\o033[39m/' -e 's/\(.*FATAL.*\)/\o033[31m...
...with information from an associated table, you can JOIN the associated table into the statement. Example Let's say you have a database schema where an Employee belongs_to :department...
Now you need to backfill existing Employee records with the new department_name. Since the department's name lives in another table, you need to JOIN both tables during...
...driver_opts directly. However, this is deprecated and will be removed in version 4 of selenium-webdriver. Version 5.x will drop support for passing the service options as hash...
...Option 2: Connect tests to a manually started chromedriver Warning This does not work with selenium-webdriver > 4 anymore. You can pass in a specific port as attribute of the...
This guide shows how to create an AngularJS application that consumes more and more memory until, eventually, the browser process crashes on your users. Although this guide has been written...
...for Angular 1 originally, most of the advice is relevant for all client-side JavaScript code. How to observe memory consumption To inspect the amount of memory consumed by your...
The benefit of the Rails asset pipeline is that it compiles your stylesheets and javascripts to a single file, respectively. However, the consequences are startling if you don't understand...
...all your asset libraries in the same folder, which quickly becomes confusing as your set of assets grows. To overcome this, we have two different solutions. Custom solution
Option 1: Creating a self-signed certificate with the openssl binary As igalic commented on this gist. openssl req -new -newkey rsa:2048 -sha256 -days 365 -nodes -x509 -keyout server.key...
make it an X.509 certificate, not a Certificate Signing Request. Option 2: Creating a self-signed certificate with the mkcert binary The linked tool mkcert helps you to setup...