Git: Removing feature branches on merge
When working with feature branches, stale branches pile up over time. It's best to remove them right after merge, locally and on the remote, but it is a little tedious: you need to remember it, and perform the few steps manually each time.
Enter Git hooks. The folks at Liquid Light have built a little post-merge hook that will delete a feature branch on confirmation....
JavaScript: Testing whether the browser is online or offline
You can use the code below to check whether the browser can make connections to the current site:
await isOnline() // resolves to true or false
The code
The isOnline()
function below checks if you can make real requests by re-fetching your site's favicon. If the favicon cannot be downloaded within 6 seconds, it considers your connection to be offline.
async function isOnline({ path, timeout } = {}) {
if (!navigator.onLine) return false
path ||= document.querySelect...
Josh McArthur: Fancy Postgres indexes with ActiveRecord
I recently wanted to add a model for address information but also wanted to add a unique index to those fields that is case-insensitive.
The model looked like this:
create_table :shop_locations do |t|
t.string :street
t.string :house_number
t.string :zip_code
t.string :city
t.belongs_to :shop
end
But how to solve the uniqueness problem?
Another day, another undocumented Rails feature!
This time, it’s that ActiveRecord::Base.connection.add_index supports an undocumented option to pass a string argument as the v...
Capybara: Most okayest helper to download and inspect files
Testing file download links in an end-to-end test can be painful, especially with Selenium.
The attached download_helpers.rb
provides a download_link
method for your Capybara tests. It returns a hash describing the download's response:
details = download_link('Download report')
details[:disposition] # => 'attachment' or 'inline'
details[:filename] # => 'report.txt'
details[:text] # => file content as string
details[:content_type] # => 'text/plain'
Features
Compared to [other approaches](...
Flexbox: How to prevent <pre> elements from overflowing
I recently had the problem that embedded code boxes crashed my layout.
It turned out that pre
s break out of their containers when using them inside a deeper nested flex layout.
For me it was a flex inside a flex item (fleXzibit).
<div class="flex">
<div class="flex-item">
...
<div class="nested-flex">
<div class="nested-flex-item">
<pre>A code example</pre>
</div>
</div>
...
</div>
</div>
The reason is that flexbox items default to `mi...
JavaScript: New Features in ES2021
tl;dr
With ES2021 you now can use
str.replaceAll()
,Promise.any()
, logical assignment operators, numeric separators andWeakRef
on all major browsers except IE11.
replaceAll
JavaScript's replace(searchValue, replaceValueOrFn)
by default replaces only the first match of a given String or RegExp.
When supplying a RegExp as the searchValue argument, you can specify the g
("global") modifier, but you have to remember doing that, hence using replace
when you expect global replacement is prone to errors.
When supplying st...
Project maintenance: four levels of code quality
Code quality can be measured in four levels:
- (Working code)
- Reliable code (minimum)
- Readable code (ok for short-lived code)
- Changeable code (standard level)
The code quality of a project directly impacts its maintainability.
Generally you should aim for level 3. If the code will stay for less than a few months, it may stay at level 2. Never go below level 1.
0. Working code
You have implemented that feature and it works. Congrats! You have reached level zero, which means three levels of code quality lie ahead.
First, m...
Components: Dynamically growing input field's height to fit content
Sometimes you will need an input field which wraps content and grows in height as soon as content gets longer than the input fields width.
There is no way to get a "normal" string input field to wrap as desired, but there are other ways.
Here is one pretty easy solution to get what you want:
Step 1
Let your input became a text area with one row.
f.text_area(:name, rows: 1, autosize: '')
Step 2
Include the autosize library in your project
yarn add autosize
And make your...
RSpec: You can super into parent "let" definitions
RSpec's let
allows you to super
into "outside" definitions, in parent contexts.
Example:
describe '#save' do
subject { described_class.new(attributes) }
let(:attributes) { title: 'Example', user: create(:user) }
it 'saves' do
expect(subject.save).to eq(true)
end
context 'when trying to set a disallowed title' do
let(:attributes) { super().merge(title: 'Hello') } # <==
it 'will not save' do
expect(subject.save).to eq(false)
end
end
end
I suggest you don't make a habit of using this regula...
Integrating ESLint
Introduction
To ensure a consistent code style for JavaScript code, we use ESLint. The workflow is similar to integrating rubocop for Ruby code.
1. Adding the gem to an existing code base
You can add the following lines to your package.json
under devDependencies
:
"devDependencies": {
"eslint": "^8.7.0",
"eslint-config-standard": "^16.0.3",
"eslint-plugin-import": "^2.25.4",
"eslint-plugin-node"...
Understanding Ruby's def keyword
This StackOverflow question about nested function definitions in Ruby imparts a good understanding of Ruby's def
.
esbuild: Make your Rails application show build errors
Building application assets with esbuild is the new way to do it, and it's great, especially in combination with Sprockets (or Propshaft on Rails 7).
You might be missing some convenience features, though.
Here we cover one specific issue:
Once you have started your development Rails server and esbuild with the --watch
option (if you used jsbundling-rails to set up, you probably use bin/dev
), esbuild will recompile your assets upon change, but build errors will only be printed to the terminal. Your application won't complain about them ...
Carrierwave: How to attach files in tests
Attaching files to a field that is handled by Carrierwave uploaders (or maybe any other attachment solution for Rails) in tests allows different approaches. Here is a short summary of the most common methods.
You might also be interested in this card if you see the following error in your test environment:
CarrierWave::FormNotMultipart:
You tried to assign a String or a Pathname to an uploader, for security reasons, this is not allowed.
If this is a file upload, please check that your upload form is multipart encoded.
Factor...
Deployment: Merge consecutive commits without cherry-picking
You want to deploy new features but the latest commits are not ready for production? Then use git merge master~n
to skip the n-last commits.
Tip
A big advantage of merging vs. cherry-picking is that cherry-picking will create copies of all picked commits. When you eventually do merge the branch after cherry-picking, you will have duplicate commit messages in your history.
Example
It's time for a production deployment!
git log --pretty=format:"%h - %s" --reverse origin/production..origin/master
0e6ab39f - Feature A
6396...
Capybara: Working with invisible elements
When Capybara locates elements in the DOM, by default it allows only accessing visible elements -- when you are using a driver that supports it (e.g. Selenium, not the default Rack::Test
driver).
Consider the following HTML:
<div class="test1">One<div>
<div class="test2">Two</div>
With some CSS:
.test1 { display: block }
.test2 { display: none }
We will be using Capybara's find
below, but this applies to any Capybara finder methods.
Default: visible: :visible
As described above, by default Capybara finds ...
Using ngrok for exposing your development server to the internet
Sometimes you need to access a dev server running on localhost from another machine that is not part of the same network. Maybe you want to use your phone to test a web page, but are only in a guest WiFi. In the past, we often used some port forwarding or other techniques to expose the service to the internet.
Enter ngrok, a command line tool that gives you an on-the-fly internet...
Caching in Rails < 6.1 may down parts of your application when using public cache control
TL;DR When using Cache-Control
on a Rails application, make sure the Vary: Accept
header is set.
Proxy caching is a good feature to serve your publicly visible application content faster and reduce load on your servers. It is e.g. available in nginx, but also affects proxies delivered by ISPs.
Unfortunately, there is a little problem in Rails < 6.1 when delivering responses for different MIME-types. Say you have an arbitrary route in your Rails application that is able to respond with regular HTML and JSON. By sending the specific ...
Spreewald 4.3.3 released
Field error steps
Spreewald's The ... field should have an error
and The ... field should have the error ...
steps now have built-in support for Rails and Bootstrap (v3-v5) error classes. When using Bootstrap, it is no longer necessary to overwrite the steps in your project.
At the same time, support for formtastic has been removed as there were no real use cases. Due to that, no breaking change was introduced, as the amount of users affected by this should be zero (it was neither in the documentation nor tested).
Users may now add...
Google Chrome now has a JavaScript bundle visualizer
Similar to the Webpack Bundle Analyzer, Chrome's new Lighthouse feature …
… shows a visualisation of your JavaScript bundles. It's compatible with sourcemaps and is great for understanding large JavaScript modules used by your page. It can also visualise unused bytes.
This is very helpful to visualize Javascript files in development. It also works on production code, where its usefulness depends on the structure of the productive Javascr...
Finding ancestors with Capybara
Modern versions of Capybara include a finder method #ancestor
which allows you to find a parental element using CSS or XPath.
If you previously did something like this:
field.find(:xpath, './ancestor::div[contains(@class, "form-group")]')
..and prefer CSS, you may rewrite it:
field.ancestor('div.form-group')
Both versions will return the outermost matching element. Use the #order
option find the closest parent:
field.ancestor('div.form-group', order: :reverse)
Ensure passing Jasmine specs from your Ruby E2E tests
Jasmine is a great way to unit test your JavaScript components without writing an expensive end-to-end test for every small requirement.
After we integrated Jasmine into a Rails app we often add an E2E test that opens that Jasmine runner and expects all specs to pass. This way we see Jasmine failures in our regular test runs.
RSpec
In a [feature spec](https://web.archive.org/web/20150201092849/http://www.rel...
Using feature flags to stabilize flaky E2E tests
A flaky test is a test that is often green, but sometimes red. It may only fail on some PCs, or only when the entire test suite is run.
There are many causes for flaky tests. This card focuses on a specific class of feature with heavy side effects, mostly on on the UI. Features like the following can amplify your flakiness issues by unexpectedly changing elements, causing excessive requests or other timing issues:
- Lazy loading images
- Autocomplete in search f...
Setup Sidekiq and Redis
If you want Sidekiq to be able to talk to Redis on staging and production servers, you need to add the following to your configuration:
# config/initializers/sidekiq.rb
require 'sidekiq'
Sidekiq.configure_client do |config|
config.redis = { url: REDIS_URL }
end
Sidekiq.configure_server do |config|
config.redis = { url: REDIS_URL }
end
The following step may be skipped for new Sidekiq 6+, since it isn't recommended anymore to use a global redis client.
# config/initializers/redis.rb
require 'redis'
require_relativ...
Fix REPL of better_errors page
The gem better_errors offers a detailed error page with an interactive REPL for better debugging.
I had the issue that on a few projects with Ruby 2.5.8
, the REPL was not shown.
Solution
To make the REPL work properly with this Ruby version I had to update the gem binding_of_caller to at least version 0.8.0
.
From the [better_errors](https://github.com/BetterE...