Cucumber up to version 2 had a neat feature called Step Argument Transforms which was dropped in favor of Cucumber 3 ParameterTypes. While I strongly encourage you to drop your legacy Transforms when upgrading to Cucumber 3, it might not always be possible due to their different design.
This is a guide on how to keep the exact same functionality of your old Transforms while writing them in the style of new `Paramet...

Until Capybara 2, node finders that accept a text option were able to find nodes based on rendered text, even if it spans over multiple elements in the HTML. Imagine a page that includes this HTML:

<div class='haystack'>
  Hi!
  <br>
  Try to match me.
</div>

Even though the text is separated by a <br> tag in the HTML, it is matched until Capybara 2 which used to "squish" text prior to the comparison.

# Capyabara 1 or 2
page.find(...

Download buttons can be difficult to test, especially with Selenium. Depending on browser, user settings and response headers, one of three things can happen:

• The browser shows a "Save as..." dialog. Since it is a modal dialog, we can no longer communicate with the browser through Selenium.
• The browser automatically downloads the file without prompting the user. For the test it looks like nothing has happened.
• The browser shows a binary document in its own window, like a PDF. Capybara/Selenium freaks out because there is no HTML docum...

If you struggle with a /boot partition that is too small for updates, and you are too intimidated by the way to resize your /boot partition, there might be an easier fix:

It is possible to configure a better compression algorithm for the images in /boot. To do this, edit /etc/initramfs-tools/initramfs.conf and change the existing line to

COMPRESS=xz

Then rebuild the images using

sudo update-initramfs -u -k all

If you get an error during the last step, please immediately get help, because otherwise...

Along with a number of other cool new features and performance improvements, Ruby 2.6 added function composition to the Proc and Method classes. Today we’ll take a look at how this allows us to use some functional programming goodness in our Ruby code.

Was ist Elastic?

• Suchmaschine, basierend auf Apache Lucene
• größtenteils Open-Source
• einige kommerzielle Features ("Elastic Stack", früher "X-Pack")
  • Zugriffsrechte (bis vor kurzen)
  • Monitoring
  • Reporting
  • Graph-Unterstützung
  • Machine Learning
• REST-Api (JSON über HTTP)

Grundlagen

Elastic antwortet per Default auf Port 9200

http GET :9200

{
  "name": "ntK2ZrY",
  "cluster_name": "elasticsearch",
  "cluster_uuid": "Bbc-ix5bQZij5vfFU29-Cw",
  "version": {
    "number": "6.7.1",
    "build_flavor": "...

PostCSS is a tool for transforming styles with JS plugins. In Webpacker you can configure the plugins and their settings via the postcss.config.js file. Make sure that postcss-loader is part of your package.json.

module.exports = {
  plugins: [
    require('postcss-import'),
    require('postcss-flexbugs-fixes'),
    require('postcss-preset-env')({
      autoprefixer: {
        flexbox: 'no-2009'
      },
      stage: 3
    })
  ]
}

Note: Stage 3 means you can use all CSS features that ar...

When doing some meta-programming magic and you want to do something for all attributes of a class, you may need to access connection or some of its methods (e.g. columns) during class definition.

While everything will be fine while you are working on a project that is in active development, the application will fail to boot when the database is missing or has no tables. This means that Raketasks like db:create or db:migrate fail on a freshly cloned project.

The reason is your environment.rb which is loaded for Raketasks and calls...

This is a short overview of things that are required to upgrade a project from the Asset Pipeline to Webpacker. Expect this upgrade to take a few days even the diff is quite small afterwards.

Preparations

1. Find all libraries that are bundled with the asset pipeline. You can check the application.js and the application.css for require and import statements. The source of a library is most often a gem or a vendor directory.
2. Find an working example for each library in the application and write it down.
3. Find out the ver...

Webpacker is Rails' way of integrating Webpack, and version 4 has been released just a few days ago, allowing us to use Webpack 4.

I successfully upgraded an existing real-world Webpack 3 application. Below are notes on everything that I encountered.
Note that we prefer not using the Rails asset pipeline at all and serving all assets through Webpack for the sake of consistency.

Preparations

• Remove version locks in Gemfile for webpacker
• Remove version locks in package.json for webpack and webpack-dev-server
• Install by ca...

1. Class-level process definitions are only applied to the original file
2. Versions are generated based on the processed original file
3. Callbacks (before/after) are applied to original file and each version by itself
4. Under the hood, a version is an instance of the uploader class that has no versions
5. Version uploader and original uploader can be distinguished by checking #version_name: version uploaders return the version name, whereas the original uploader instance returns nil
6. Version instances do not have a re...

If your app does not need to support IE11, you can use most ES6 features without a build step. Just deliver your plain JavaScript without transpilation through Babel or TypeScript, and modern browsers will run them natively.

Features supported by all modern browsers include:

• fat arrow functions (() => { expr })
• let / const
• class
• async / await
• Promises
• Generators
• Symbols
• Rest arguments (...args)
• Destructuring

You won't be able to use import and export, or use npm modules.

See this [ES6 compatibility mat...

Cucumber factory supports polymorphic associations out of the box. Just keep in mind that you need to use named associations for this purpose.

class Person < ApplicationModel
  has_many :buildings, inverse_of: :owner
end

class Company < ApplicationModel
  has_many :buildings, inverse_of: :owner
end

class Building < ApplicationModel
  belongs_to :owner, optional: true, polymorphic: true
end

Works

Given there is a person with the name "Nice person"
  And there is a bui...

Cucumber has an output format that prints step definitions only. You can use this to find unused ones:

1. Temporarily add require_relative 'env' to the top of the first file in features/support. --dry-run makes Cucumber skip loading env.rb.
2. Open a really wide terminal window.
3. bundle exec cucumber --dry-run --format stepdefs | grep -B1 'NOT MATCHED' --no-group-separator | grep features/step_definitions

This will print all unused step definitions from your project – however, the result will include false positives. Step...

When upgrading Rails versions -- especially major versions -- you will run into a lot of unique issues, depending on the exact version, and depending on your app.

However, it is still possible to give some generic advice on how you want to tackle the update in principle.

If you are not really confident about upgrading Rails, have a look at Rails LTS.

How many update steps?

Besides the Rails upgrade itself, you might also want to upgrade your other gems and upgrade your Ruby version.
First decide in how many st...

The Ace editor is a great enhancement when you want users to supply some kind of code (HTML, JavaScript, Ruby, etc).
It offers syntax highlighting and some neat features like auto-indenting.

For Webpack 3+

Integrate as described in the documentation. For example load ace Editor like this:

  function loadAceEditor() {
    return import(/* webpackChunkName: "ace" */ 'ace-builds/src-noconflict/ace').then(() => {
      return import(/* webpackChunkName: "ace" */ 'ace-builds/webpack-r...

New Features

• Deployment ready for Opscomplete
• Copying view and controller templates over to target application during
  basics configuration or via new command katapult templates.
• "Usage" section in README rewritten: Now describes two usage scenarios.

Improvements

• Generating a fixed Gemfile.lock. Run bundle update after code generation to
  update all gems to recent versions.
• Better deployment with Webpack
• Navigation only rendered if requested
• Some minor fixes

Accessing pseudo elements via JavaScript or jQuery is often painful/impossible. However, accessing their styles is fairly simple.

Using getComputedStyle

First, find the element in question.

let element = document.querySelector('.my-element') // or $('.my-element').get(0) when using jQuery

Next, use JavaScript's getComputedStyle. It takes an optional 2nd argument to filter for pseudo elements.

let style = window.getComputedStyle(element, '::before')
let color = style.getPropertyValue('background-color...

When you are using lambdas in RSpec to assert certain changes of a call, you know this syntax:

expect { playlist.destroy }.to change { Playlist.count }.by(-1)

While you can define multiple assertions through multiple specs, you may not want to do so, e.g. for performance or for the sake of mental overhead.

Multiple expectations on the same subject

RSpec allows chaining expectations simply by using and.

expect { playlist.destroy }
  .to change { Playlist.count }.by(-1)
  .and not_change { Video.count }

...

Percent Notation

We already know that that we can create strings using the percent notation:

%(<foo="bar's ton">) is perfectly fine Ruby.

Modifier

But there is more. The curly brackets ({}) are interchangable with most unicode characters (e.g. square brackets[]).
Furthermore, you can add a "modifier" to the percent notation to control the return type of th...

Geordi uses parallel_tests if available for running the test suite. To debug an application it is very unhandy to have multiple processes as your terminal I/O will not work as expected once a breakpoint is hit.

Even parallel_tests support an option to enable a single process run, it is not possible to pass this option through geordi. But you can set the number of processes via ENV variable manually:

PARALLEL_TEST_PROCESSORS=1 bundle exec geordi cucu...

Font Awesome 5 is a comprehensive solution for vector icons on your website.

Originally, Font Awesome came as an icon font (plus stylesheets), but recently it can also be used as a pure JavaScript solution (which will render icons as inline <svg> tags), or even as SVG sprites.

All solutions have their pros and cons:

Icon font:

• little CPU load (no JavaScript)
• fonts are relatively large
• 1 extra HTTP request

Javascript + inline SVG:

• higher CPU load (needs to watch the DOM via mutation observers to ad...

Masonry is a famous library to dynamically arrange a grid of items that have different aspect ratio, like horizontal and vertical images.
Colcade is an alternative masonry-layouting library, developed by the same developer, but with a more modern approach.

It is said to have better performance while being smaller and having no dependencies. It automagically detects jQuery and defines a jQuery initializer, if present.
However, it offers [a few less features](https:...