kchens

Notes on Backbone and Everything Else

Backbone

Todo app

I've included a link to a simple Todo application built in backbone with a detailed commit history. I would recommend going through the repo from the first commit to the last. It should be clear what

kchens

require 'stock_quote'
require 'pp'
 
class StocksController < ApplicationController
  before_action       :load_user
  skip_before_filter  :verify_authenticity_token
 
  def index
    update_stocks
  end

kchens

# ######################
# Refactored
# ######################


# app/controllers/stocks_controller.rb
 
require 'stock_quote'
require 'pp'
 

kchens

# ######################
# Refactored
# ######################
 
# app/services/stock_service.rb
class StockService
  def initialize(user)
    @user = user
    @stocks = []
    @stock_symbols = []

kchens

# 1 -------------------BAD
class Gear
  attr_reader :chainring, :cog

  def initialize(chainring, cog)
    @chainring = chainring
    @cog = cog
  end

  def ratio

kchens

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
# Needs to Manage Dependencies

class Gear
  attr_reader :chainring, :cog, :rim, :tire

  def initialize(chainring, cog, rim, tire)
    @chainring = chainring
    @cog  = cog
    @rim = rim

kchens

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
# Law of Demeter
# set of coding rules that results in loosely coupled objects. It prohibits
# routing a message to a third object via a second object of a different type.
# Paraphrased:  "only talk to your immediate neighbors", "use only one dot"

class Trip

  def depart
    # "train wrecks"

kchens

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
# Overlooking Ducks

# 1 -------------------BAD

class Trip
  attr_reader :bicycles, :customers, :vehicle

  def prepare(mechanic)
    # no depedency on mecahnic

kchens

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
# Starting Class

# 1 -------------------Okay

class Bicycle
  attr_reader :size, :tape_color

  def initialize(args)
    @size         = args[:size]

kchens

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
# Writing the Concrete Code

# 1 -------------------Bad

class Schedule
  def scheduled?(schedulable, start_date, end_date)
    puts "This #{schedulable.class} " +
          "is not scheduled\n" +
          " between #{start_date} and #{end_date}"