kadru

#Safe navigation operator
if account && account.owner && account.owner.address
  #your code here
end
#could be rewritten like
account&.owner&.address

#more examples
account = Account.new(owner: nil) # account without an owner
#

kadru

#get env variables of a process
sudo xargs --null --max-args=1 < /proc/<pid>/environ

#get command of a process
ps -fp <pid>
cat /proc/<pid>/cmdline

kadru

 #dwarf.rb
class Dwarf
  include Comparable

  def initialize(name, age, beard_strength)
    @name           = name
    @age            = age
    @beard_strength = beard_strength
  end

kadru

Webpack in Rails

All code is available in example app - https://github.com/maxivak/webpacker-rails-example-app

Table of Contents

• NPM and Yarn
• Webpack and Webpacker

kadru

module RunStrategies
  class RunStrategyInterface
    def self.run(name)
      raise "Run method has not been implemented!"
    end
  end

  class Jog < RunStrategyInterface
    def self.run(name)
      puts "#{name} is now jogging at a comfortable pace."

kadru

SELECT DATA_TYPE 
FROM INFORMATION_SCHEMA.COLUMNS
WHERE 
     TABLE_NAME = 'yourTableName'
     COLUMN_NAME = 'yourColumnName'

kadru

class DatabaseHelper
  def self.select name, *args, &blk
    execute "select", name, *args, &blk
  end

  def self.call name, *args, &blk
    execute "call", name, *args, &blk
  end

  def self.execute via, name, *args, &blk

kadru

##
# This files shows some possible implementations of the Singleton pattern
# in Ruby. I'm not a huge fan of the Singleton pattern, but it's nice
# in some cases. In this file I'm going to implement a simple logger.
#


##
# The first implementation that can come to our minds is to create a class
# that holds an instance as a class variable that can be accessed through

kadru

#With the macOS El capitan
#check git version
git --version
#Backup (or remove) Apple git (Optional)
sudo mv /usr/bin/git /usr/bin/git-apple
#Install Homebrew if you didn’t have
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
#Or update if you already have
brew update && brew upgrade
#Install Git with Homebrew

kadru

EXEC sp_change_users_login 'Auto_Fix', 'user', NULL, 'pass'

-- constraints information
SELECT * FROM sys.objects
WHERE type_desc LIKE '%CONSTRAINT'

SELECT *
 FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
 where CONSTRAINT_NAME = 'constraint_name'