Browsers come with a set of built-in elements like <p> or <input>. When we need a new component not covered by that, we often build it from <div> and <span> tags. An alternative is to introduce a new element, like <my-element>.

When a browser encounters an unknown element like <my-element>, the browser will proceed to render <my-element>'s children. The visual rendering of your page will not be affected.

If you care about their HTML being valid, your new element should contain a dash character (-) to mark it as a *custom el...

A primer on vector graphics

For rastered image formats like JPG or PNG, each pixel is basically drawn on a fixed size canvas. To display such an image in a different size (say: 1.5 times larger than original), the renderer (your Browser / GPU / Monitor) needs to interpolate the color values of missing pixels. The image will appear slightly blurred.

This is different for vector graphics like the SVG (Scalable Vector Graphics) format. You can imagine SVG files as XML file contai...

The problem:

So I had the issue that User input (coming from many different sources and users) often contains the same long word. Maybe that's a super german thing to have lots of long words I have to deal with. This long word needs to be fully visible on small screens but none of the automated word-break solutions offered by css (https://justmarkup.com/articles/2015-07-31-dealing-with-long-words-in-css/) is clever or supported enough to be a good solution. So I...

This collection contains some useful design resources for developers. Many of them were mentioned in the Refactoring UI tutorials.

Tutorials

• Refactoring UI Videos
• Refactoring UI Book
• Refactoring UI Chapter Color Palette
• Refactoring UI Chapter Line Height
• [Law...

Introduction

Most of the time it is a tedious task to apply a code style guide to an existing code base as there are likely to be a lot of conflicts. At makandra we are using makandra-rubocop to have code style checks. Here is some advice on how to add makandra-rubocop efficiently.

Note

RubyMine by default has a Rubocop inspection with rules that we don't always agree with. We recommend replacing this with makandra-rubocop or disabling the inspection.
...

CSS transitions are a simple animation framework that is built right into browsers. No need for Javascript here. They're supported by all browsers.

Basic usage

Transitions are used to animate the path between to property values. For example, to let the text color fade from red to green on hover, the following SASS is used (shorthand syntax):

.element
  color: red
  transition: color .1s
  
  &:hover
    color: green

This tells the browser "whenever the color of an .element changes...

Within a Flexbox layout, there are multiple CSS attributes that may affect a child's basis (the initial width before flexing). You might be confused how flex-basis, width, min-width and the intrinsic width of your content play together.

The attached article explains the differences. In summary:

• If a flex-basis is set, that is used as the basis
• If no flex-basis is set, the width is used as the basis
• If neither flex-basis nor width is set, the content...

General hints on the DOM

• the root of the DOM is document
• custom elements inherit from HTMLElement. They need a - (dash) in their name, e.g. <notification-box>.
• event listeners don't have event delegation à la .on('click', cssSelector, handler)

Comparison

When an AJAX request raises an exception on the server, Rails will show a minimal error page with only basic information. Because all Unpoly updates work using AJAX requests, you won't get the more detailled better_errors page with the interactive REPL.

Below is an event listener that automatically repeats the request as a full-page load if your development error shows an error page. This means you get...

webpack is a very powerful asset bundler written in node.js to bundle (ES6) JavaScript modules, stylesheets, images, and other assets for consumption in browsers.

Webpacker is a wrapper around webpack that handles integration with Rails.

This is a short introduction.

Installation

If you haven't already, you need to install node.js and Yarn.

Then, put

gem 'webpacker', '~> 4.x' # check if 4.x is still cu...

RubyMine comes with a nice way to grep through your project's files: The finder (ctrl + shift + f). Don't be discouraged about the notice 100+ matches in n+ files if your searched keyword is too general or widely used in your project.

RubyMine comes with a few ways to narrow down the resulting list, don't hesitate to apply those filters to speed up your search. Your keybinding might vary based on your personal settings.

File mask (alt + k)

If you already know the file extension of your ...

The goal is to get Jasmine specs running in a Rails project using Webpacker, with the browser based test runner. Should be easily adaptable to a pure Webpack setup.

Step 1: Install Jasmine

yarn add jasmine-core

Step 2: Add two separate packs

Since we do not want to mix Jasmine into our regular Javascript, we will create two additional packs. The first only contains Jasmine and the test runner. The second will contain our normal application code and the specs themselves.

We cannot...

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(...

It is quite easy to migrate from CoffeeScript to ES6. You can use decaffeinate to convert your CoffeeScript source to modern JavaScript.

Install decaffeinate globally:

npm install -g decaffeinate

Call decaffeinate on each .coffee file, relaxing some options to get the most modern (and concise) JS:

decaffeinate file.coffee --use-cs2 --loose --optional-chaining --logical-assignment

Tip

If you use Babel and see errors while decaffeinati...

To keep JavaScript sources small, it can sometimes make sense to split your webpack bundles. For example, if your website uses some large JavaScript library – say TinyMCE – which is only required on some selected pages, it makes sense to only load that library when necessary.

In modern webpack this is easily doable by using the asynchronous import function.

Say we have an unpoly compiler that sets up TinyMCE like this (code is somewhat simplified):

// TinyMCE as part of the main bundle!

import tinymce from 'tinymce/tinymce'

// U...

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...

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...

Many mail clients do not support external style sheets. Some even require all styling inline, which means you'll have to do your styling inline. For Rails applications, you can use Roadie or premailer, which lets you keep your well-structured CSS files and do the inlining for you.

See Designing HTML email

Since Roadie is now in passive maintenance mode, we go with premailer:

Include premailer in your Gemfile:

gem 'premailer-ra...

min-width is known as a CSS property that can be set to define a least width for an element. Surprisingly, it can also be used to set something that feels like max-width.

min-width in a flex context

While the default min-width value is 0 (zero), for flex items it is more like "auto". This can make block elements take up much more space than desired, even stretching their container beyond the screen edge on small screens.

![Image](/makandra/66994/attach...

Here is how to make Rome datepicker look like the rest of your Bootstrap 4 application.

Rome comes with very little basic styling. While we could redefine its classes, we can configure the classes Rome applies to its elements to make it look like this:

Since Bootstrap 4 comes with several helpful utility classes, and requires fewer markup/containers, we can achieve Bootstrap 4 experience by applying a few classes via the styles setting.

You still need to include `ro...

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...