stevecass

h1 = Hash.new          # => {}
h2 = Hash.new("a")     # => {}
h3 = {}                # => {}
h4 = {abc: "def"}      # => {:abc=>"def"}
h5 = {:abc => "def"}   # => {:abc=>"def"}
h6 = {"abc" => "def"}  # => {"abc"=>"def"}

h1["abc"]  # => nil

h1.fetch("abc", "kitty")  # => "kitty"

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#Creating an app called my_great_app

rails new my_great_app -T -d postgresql --skip-turbolinks
cd my_great_app
git init
git add .
git commit -m "Initial commit. Rails boilerplate."

# Edit gemfile
# #Remove the reference to coffee-rails.

stevecass

/*

Prerequisite: meteor add peerlibrary:aws-sdk
Terminology: 
AWS: Amazon web services
S3: Simple storage service (one of the above.)


Create a bucket on S3. Use AWS Identity and Access Manager to create 
a user that your app can log in as . Attach a policy to that user 

stevecass

Moving to Rails from Sinatra

Helpers

Helper methods in rails are used only in views, not controllers. If you want to make a method available to multiple controllers, you can declare it in the ApplicationController, which is the base class for all your controllers. If you want the method to be visible to views, declare it as a helper_method.

http://api.rubyonrails.org/classes/AbstractController/Helpers/ClassMethods.html#method-i-helper_method

stevecass

class Post < ActiveRecord::Base
  has_many :comments, as: :commentable
end

class Photo < ActiveRecord::Base
  has_many :comments, as: :commentable
end

class Comment < ActiveRecord::Base
  belongs_to :commentable, polymorphic: true

stevecass

import UIKit

let nonOptionalVar: [String] = ["a", "b", "c"]
let optionalVar:String? = "jimmy"

// this compiles OK with import UIKit present
let ex1: [String: AnyObject] = ["key" : nonOptionalVar, "notherkey": ["content": optionalVar!]]

// Here we forget the ! character that unwraps the optional
// error: contextual type 'AnyObject' cannot be used with dictionary literal

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<key>NSAppTransportSecurity</key>
  <dict>
    <!--Include to allow all connections (DANGER)-->
    <key>NSAllowsArbitraryLoads</key>
    <true/>
  </dict>

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# Model files

class Match < ActiveRecord::Base
  belongs_to :source, foreign_key: 'from_id', class_name: Personality
  belongs_to :target, foreign_key: 'to_id', class_name: Personality
end

class Person < ActiveRecord::Base
  belongs_to :personality

stevecass

// ES 6 basics

setTimeout(() => {
  console.log('Hello');
  console.log('Goodbye');
}, 200);

// One - liners can omit the { }
// and implicitly return the value of their statement
setTimeout(() => 5, 200)

stevecass

//variables declared in global scope become properties of the window in browser environments
var a = 123;
console.log('a', window.a);

// functions introduce scope. A variable declared inside a function is not visible outside
function f() {
  var b = 456;
  console.log('b', b);
  // inside the function we can still see the global a. We don't need "window." - it's implied
  console.log('a', a);