Five years of "Today I Learned" from Josh Branchaud

The linked GitHub repository is a bit like our "dev" cards deck, but groomed from a single person (Josh Branchaud). It includes an extensive list of over 900 TILs on many topics that might be interesting for most of us. (e.g. Ruby, Rails, Git, Unix..)

Ruby

Here is an excerpt of all the Ruby TILs Show archive.org snapshot that were new to me. I encourage you to take your time to skim over the original list as well!

• Assoc For Hashes Show archive.org snapshot
  • Hash#assoc can be used to grab both the key and value from a hash
• Rerun Only Failures With RSpec Show archive.org snapshot
  • RSpec can be configured to run only failed specs:

CopyRSpec.configure do |config|
  config.example_status_persistence_file_path = "tmp/failed_specs.txt"
end
# Then, run "rspec --only-failures"

• Disassemble Some Codes Show archive.org snapshot
  • RubyVM::InstructionSequence#compile can be used to compile Ruby code on the fly. It offers a #disasm method for further inspection.
• Destructuring Arrays In Blocks Show archive.org snapshot

Copy{ key: [1,2] }.each { |key, (x, y)| puts "#{x}- #{y}" }

• Defaulting To Frozen String Literals Show archive.org snapshot
  • This magic string auto-assigns freeze to constants of a given file

Copy# frozen_string_literal: true

• Listing Local Variables Show archive.org snapshot

Copybinding.local_variables.inspect

• Limit Split Show archive.org snapshot
  • String#split takes a second argument to limit the number of applied splits
• Last Raised Exception In The Call Stack Show archive.org snapshot
  • The $! global variable contains the last exception that was raised in the current call stack
• Identify Outdated Gems Show archive.org snapshot
  • bundle outdated compares the versions of all gem dependencies against the gem server
• Get Info About Your Ruby Gems Environment Show archive.org snapshot

Copygem environment

• Mocking Requests With Partial URIs Using Regex Show archive.org snapshot
  • Note the elegant way to describe Regex URLs: %r|/foo/bar|

Copystub_request(:post, %r|/api/posts|)

• Pass A Block To Count Show archive.org snapshot
  • count can be used like "count by":

Copy[1,2,3].count { |x| x.odd? }

• Parallel Bundle Install Show archive.org snapshot

Copybundle install --jobs 4

• Run An Older Version Of Bundler Show archive.org snapshot
  • Fun fact: This TIL links back to makandracard! :-)

Copybundle _1.16.6_ --version

• String Interpolation With Instance Variables Show archive.org snapshot

Copyputs "I am #@name"

• Squeeze Out The Extra Space Show archive.org snapshot
  • String#squeeze is like String#squish but replaces multiple subsequent occurrences of a given character with a single one
• Use Tap For Better Test Data Setup Show archive.org snapshot

Copy  let(:order) do
    create(:order, name: "My Order").tap do |order|
      create(:item, name: "Burger", order: order, price: 4.99)
      create(:item, name: "Fries", order: order, price: 2.99)
    end
  end

• Next And Previous Floats Show archive.org snapshot

CopyFloat#next_float
Float#previous_float

Chrome

• On the developer console, copy data to the system clipboard with copy('data').

Git

• Executing a bash command in each step of an interactive rebase Show archive.org snapshot
• Finding a commit by commit message using regular expressions with git show :/regex Show archive.org snapshot
• Show commits touching a given line(s) with git log -L12:25:README.md Show archive.org snapshot
• Controlling git add -p with single key presses Show archive.org snapshot
• Stash unstaged changes only with git stash -k Show archive.org snapshot

JavaScript

• Create an object with no properties with Object.create(null) => {} Show archive.org snapshot
• The comma operator returns its last expression Show archive.org snapshot