Cheat Sheet for the modern DOM API

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', cssSel...

The following snippet demonstrates how you could create excel files (with spreadsheet gem) and format columns so that they follow a specific number format like currencies or dates do.

require 'rubygems...

Be careful!
The following solution will delete files on a volume. If you don't know exactly what you're doing, you can run into big trouble with your computer.

I play mp3 files on my car stereo that are stored on a SD-C...

When you render a nested form for a Movie which has_many :actors, you want to render the right number of blank Actor forms. The right number means:

• A minimum number of blank forms so the user can add more Actors to an existing Movie, ...

When your Cucumber feature needs to browse the page HTML, and you are not sure how to express your query as a clever CSS or XPath expression, there is another way: You can use [all](http://rubydoc.info/github/jnicklas/capybara/master/Capybara/No...

In Ruby (almost) everything is an Object. While this enables a lot of powerful features, this concept might be confusing for developers who have been programming in more static languages, such as Java or C#. This card should help understanding t...

While upgrading CarrierWave from version 0.11.x to 3.x, we encountered some very nasty fails. Below are the basic changes you need to perform and some behavior you may eventually run into when upgrading your application. This aims to save you some...

When you build a JSON API you need to come up with a style to represent attributes, pagination, errors or including associated objects. Instead of reinventing the wheel, you may reuse successful API designs.

JSON API

[JSON:API](https://...