thiagofm

module FlippedTable
  def table
    "┻━┻"
  end
end

class AngryTableFlipper
  # Including FlippedTable's methods...
  # as instance methods
  include FlippedTable

thiagofm

# Let's define a FlippedTable class
module FlippedTable
  # Define method we want to use in different classes
  def table
    "┻━┻"
  end
end

class AngryTableFlipper
  # Include it to a class that will use it

thiagofm

class Wheel
  def tire
    puts "Tire is flat, needs service"
  end
end

Wheel.new.tire
# Tire is flat, needs service

module SpareTire

thiagofm

# Bang method behavior: upcase!

email = "[email protected]"
# Upcasing a string, but not changing the variable email's value
email.upcase
#  => "[email protected]"
email
# => "[email protected]"

# Using bang to upcase a string

thiagofm

# Using OpenStruct to mimic an object with the 'posts method'
user = OpenStruct.new(posts: [:post1, :post2])

# Using if user as a nil checker
user.posts if user
# => [:post1, :post2]

# Can be replaced with the safe navigation operator
user&.posts
# => [:post1, :post2]

thiagofm

# Ruby 3.1+

users = [
  { name: "Yukihiro Matsumoto", age: 57 },
  { name: "Kabosu the Shiba Inu", age: 16 },
  { name: "Thiago Massa", age: 33 }
]

def fetch_age_from_person(person, hash)
  hash => [*, {name: ^person, age: age}, *]

thiagofm

class PlaySong
  def initialize(song)
    @song = song
  end

  def call
    # Here you implement your service object
    "🎶 #{song}"
  end

thiagofm

# Creating a complex hash, with nested keys 
my_complex_hash = {
  users: [
    {name: "Yukihiro Matsumoto", age: 57},
    {name: "Kabosu the Shiba Inu", age: 16},
    {name: "Thiago Massa", age: 33}
  ]
}

thiagofm

# Ruby pattern matching based on Type (=> operator)
[1,2,3] => [1, Integer, my_variable]
# This means:
# We want to assign `my_variable` (variable binding), 
# but only if the first position is 1 and second position is an Integer)
my_variable # => 3 ✨

# What if it doesn't match? You get an exception 💣
[1,2,3] => [Integer, String, my_variable]
# [1, 2, 3]: String === 2 does not return true (NoMatchingPatternError)

thiagofm

web: rdbg -n --open=vscode -c -- bin/rails server -p 3000
js: yarn build --watch