Summary

• We want to move away from jQuery in future projects
• Motivations are performance, bundle size and general trends for the web platform.
• The native DOM API is much nicer than it used to be, and we can polyfill the missing pieces
• Unpoly 0.60.0 works with or without jQuery

Is jQuery slow?

```text
From: Sven
To: unpoly@googlegroups.com
Subject: performance on smartphones and tablets

Hello

I just used your framework in one project and must say,
I am really pleased with it – but only on a desktop computer.

Have you benchm…

Carrierwave includes some handy helper methods you can use to resize your images. Here is a quick summary of them, if you need more details read the docs. You can also use all command line options from RMagick directly if these helpers are not good enough for you.

```
resize_to_limit(width, height)
resize_to_fit(width, height)
resize_to_fi…

Capybara will fail to find <a> tags that are missing an href attribute. This will probably happen to you every now and then on JavaScript-heavy applications.

An example would be an AngularJS application where the following HTML actually works. [1]

<a ng-click="hello()">Hello</a>

Capybara will fail to find that link, even though looking it up via the DOM shows it:

>> find_link("Hello")
Capybara::ElementNotFound: Unable to find link "Hello"

>> find("a").text
=> "Hello"

To make find_link and click_link work…

Spammers have started abusing other application to send their spam. This works like this:

• The application has some form that allows to send e-mails to arbitrary users. This can be something like a newsletter sign-up with a double-opt in, a registration confirmation e-mail (or even password reset e-mail), or something similar.
• The e-mail also includes some reflected text. For example, a user may be able to give their name, and the name is used within the e-mail. The spammer will then abuse that text to include his advertisment.

Potentia…

In Rails 3+, you can use:

class Project
  delegate :url_helpers, to: 'Rails.application.routes'

  def project_path
    url_helpers.project_path(self)
  end
end

For Rails 2, use the attached Modularity trait. It will give any Ruby class a method #url_writer, on which you can call URL helpers:

class Foo
  does 'write_urls'
  def self.class_method
    url_writer.session_path
  end
  def instance_method
    url_writer.project_path(5)
  end
end

Why string sorting sucks in vanilla Ruby

Ruby's sort method doesn't work as expected with German umlauts:

["Schwertner", "Schöler"].sort
=> ["Schwertner", "Schöler"] # you probably expected ["Schöler", "Schwertner"]

Also numbers in strings will be sorted character by character which you probably don't want:

["1", "2", "11"].sort
# => ["1", "11", "2"] # you probably expected ["1", "2", "11"]

Also the sorting is case sensitive:

["a", "B"].sort
# => ["B", "a"] # yo...

When building an application that sends e-mails to users, you want to avoid those e-mails from being classified as spam. Most obvious scoring issues will not be relevant to you because you are not a spammer.

However, your application must do one thing by itself: When sending HTML e-mails, you should include a plain-text body or tools like SpamAssassin will apply a significant score penalty. Here is how to do that automatically.

1. Add premailer-rails to your Gemfile and bundle.
2. Done! …

Scrolling overflowing elements with JavaScript

HTML elements with overflow-y: auto or overflow-y: scroll will get a scrollbar when their content is higher than their own height.

When you scroll an element , the element's scrollTop property is updated with the scrollbar's new position. You can also set element.scrollTop = 30 to scroll the element to a vertical pixel position counted from the top.

Scrolling the main viewport with JavaScript

The browser's main document viewport is also scrollable by default. The element that …

This card tries to summarize by example the different uses of heredoc.

• In Ruby << vs. <<- vs. <<~
• In Rails strip_heredoc vs. squish

strip_heredoc should be used for a text, where you want to preserve newlines. (multi-line -> multi-line)

squish should be used for a text, where you want to squish newlines. (multi-line -> one-line)

Ruby 2.3+

def foo
  bar = <<~TEXT
    line1
    line2
    line3
  TEXT
  puts bar.inspect
end
foo => "line1\nline2\nline3\n"

Read more: [Unindent HEREDOCs in Ruby 2.3](/makan…

Suggested Workflow

Set the ruby version in .ruby-version to 2.3.5, then perform these steps one by one, fixing errors as they occur:

1) Update gems as listed below, and bundle
2) Boot a Rails console - see below for a list of changes you will probably need
3) Run Specs with --backtrace option
4) Run Cucumber features (with Geordi's --debug option)
5) When all tests are green, look through your Gemfile and remove as many version constraints as possible.
6) Boot the application in different environements to spot further issues, e…

What collapsing margins are

Imagine you have 2 HTML boxes. The first one has a margin-bottom of let's say 30px and the second one a margin-top of 20px. After rules of collapsing margins have been applied we have a margin of 30px (not 50px) between these two boxes (see this article for an illustration) . This is because no addition of both margins takes place but the maximu…

When using virtual attributes, the attached trait can be useful to automatically copy errors from one attribute to another.

Here is a typical use case where Paperclip creates a virtual attribute :attachment, but there are validations on both :attachment and :attachment_file_name. If the form has a file picker on :attachment, you would like to highlight it with errors from any attribute:

class Note < ActiveRecord::Base
  has_attached_file :attachment
  validates_attachment_presenc...

In ruby you can easily read and write CSVs with the standard CSV library class.

On top of this, you can use the gem smarter_csv for reading (not writing) CSVs in a more comfortable way:

• Keep in mind, that the development of this gem is in an unknown state and the 2.0 release seems to happen never
• The API will change completely for 2.0, so you might find a bunch of unrelated documentation for 1.2

Here is an example…

When you generate a URL in a mailer view, ActionMailer will raise an error unless you previously configured it which hostname to use. Configuring the correct hostname is quite annoying when you have multiple deployment targets with different hostnames, e.g. a staging server and a production server.

Using the hack below you don't need to configure a default hostname for your mailers. They will always use the hostname for the current request:

class ApplicationController < ActionController::Base

  before_filter :make_action_maile...