razorcd

<!--
    HTML5 data- attributes using RESTful approach
    HTML5 specifies extensible attributes like data-foo=“bar” (or as in Twitter Bootstrap data-toggle=“modal”), which poses two problems for Rails.
    
    First, if you’re using symbol notation in link_to (for instance) to specify attributes, this fails (dash is not a valid symbol character), so:
-->
    <% link_to('Edit', '../main.html', :class => "btn", :data-toggle => "modal") %> <!-- INVALID!! -->

<!--
    There are two solutions:

razorcd

bm = ->(counter=1) {
  Benchmark.measure do
    counter.times do |i|
      Sponsorship.joins(:sponsor, :orphan).
                  where("sponsor_id = ?",1).
                  select("orphans.name as orphans_name, orphans.date_of_birth as orphans_date_of_birth, orphans.gender as orphans_gender").
                  to_a
      # puts i
    end
  end

razorcd

#app/models/validators/valid_date_presence_validator.rb
 class ValidDatePresenceValidator < ActiveModel::EachValidator
  include DateHelpers

  def validate_each(record, attribute, value)
    unless valid_date? value
      record.errors[attribute] << ('is not a valid date')
    end
  end

razorcd

#spec/support/model_helpers.rb
# use like this:
# it { is_expected.to have_validation ValidDatePresenceValidator,
#                                     :on => :start_date,
#                                     :options => [:allow_blank, :allow_nil]
#                                     }
RSpec::Matchers.define :have_validation do |validator, params|
  match do |model|
    my_validators = model.class.validators.select { |v| v.class == validator and v.attributes.include? params[:on] }
    my_validators = validators.select { |v| params[:options].all? { |po| v.options.any? { |vo| vo == po } } } if params[:options]

razorcd

pg_restore -vwc -U postgres -d database_name file.dump

razorcd

# Class Specialisations  (Composition + Dependency injection)

class House
  DATA = [1,2,3,4,5,6]
  attr_reader :data

  def initialize(orderer: DefaultOrderer.new, formatter: DefaultFormatter.new)
    # @data = formatter.format(orderer.order(DATA))
    formatted_data = formatter.format(DATA)
    @data = orderer.order(formatted_data)

razorcd

Check free mem:
free -m

Add swap:
```
  sudo dd if=/dev/zero of=/swap bs=1M count=1024
  sudo mkswap /swap
  sudo swapon /swap
```

razorcd

1. install openjdk
  `sudo apt-get install openjdk-7-jdk`
  
2. install `android sdk`
  # download android sdk
  wget http://dl.google.com/android/android-sdk_r24.2-linux.tgz
  
  tar -xvf android-sdk_r24.2-linux.tgz
  cd android-sdk-linux/tools

razorcd

//simple

var var1 = 1;
var func1 = function(input) {
	//var var2 = 2;
	return input + var1; // + var2;
}

console.log(func1(1));
console.dir(func1);

razorcd

- Single Responsability - classes and methods should handle/do only one thing. Methods max 5 lines long, classes max 100 lines long.
- Open Closed - classes should be open for extension and closed for change
- Liskov Substitution - Having a main class and a subclass. Anywhere we use the main we should get same result by using the subclass.
- Interface Segragation - no client should be forced to depend on methods it does not use. Maybe class does not do only one thing? Split the class in more classes (and maybe add a facade).
- Dependency Inversion - Dont tight couple the classes by creating one instance inside another class. Inject them as dependencies when calling the method outside the class.  
                         Use `A.new(b: B.new(5))` instead of `A.new(5)` where `class A; def initialize(i); @b= B.new(i); end`

- Law of Demeter - don't chain methods that could be changed in future. (except when methods returns self)
- Don't repeat yourself - reuse code