paulirish

// everyone's new favorite closure pattern:
(function(window,document,undefined){ ... })(this,this.document);

// when minified:
(function(w,d,u){ ... })(this,this.document);

// which means all uses of window/document/undefined inside the closure 
// will be single-lettered, so big gains in minification.

// it also will speed up scope chain traversal a tiny tiny little bit.

goodmike

# The problem: In your Rails 3 project, you have a model Request that models a
# user's request for content related to a specific problem or topic. The user 
# can tag her request with any number of words. These are modeled by a Tag class
# backed by a tags DB table. Since you want unique records per tag, you have a 
# Tagging class backed by a taggings table. Taggings is a a many-to-many table
# with some additional information. Also, other models in the application 
# besides requests can be tagged: The Tagging class defines a polymorphic 
# relationship "taggable" with those models.
#
# So pretty soon you want to look up all the requests that are tagged with

dhh

describe "GET current" do
    before do
      @request.cookies['hidden_notices'] = "1,#{notices(:permanent).id}"
      get :current, :format => 'js'
    end

    it { should respond_with(:success) }
    it { should set_cookie(:hidden_notices).to("#{notices(:permanent).id}") }
    it { should render_template('notices/current') }
  end

slayer

# Simple JOIN
User.joins(:account)  # User -> Account
# Will produce
# SELECT `users`.* FROM `users` INNER JOIN `accounts` ON `accounts`.`user_id` = `users`.`id`

# Complicated JOIN
Trait.joins(:user => :account)  # Trait -> User -> Account
# Will produce
# SELECT `traits`.* FROM `traits` INNER JOIN `users` ON `users`.`id` = `traits`.`user_id` INNER JOIN `accounts` ON `accounts`.`user_id` = `users`.`id`

erichurst

# MySQL.  Versions 4.1 and 5.0 are recommended.
#
# Install the MySQL driver:
#   gem install mysql2
#
# And be sure to use new-style password hashing:
#   http://dev.mysql.com/doc/refman/5.0/en/old-client.html
development:
  adapter: mysql2
  encoding: utf8

mxriverlynn

<form action="/login" id="login-form">
  Username: <input type="text" id="username"><br>
  Password: <input type="password" id="password"><br>
  <button id="login" disabled="true">Login</button>
</form>

jcasimir

Render and Redirect

The normal controller/view flow is to display a view template corresponding to the current controller action, but sometimes we want to change that. We use render in a controller when we want to respond within the current request, and redirect_to when we want to spawn a new request.

Render

The render method is very overloaded in Rails. Most developers encounter it within the view template, using render :partial => 'form' or render @post.comments, but here we'll focus on usage within the controller.

:action

stevekrenzel

unshred = (shreddedImage, shredWidth) ->
  {width, height} = shreddedImage
  shreds = split shreddedImage, shredWidth

  weights = cross shreds, (x, y) ->
    if x == y
      0
    else
      mean zipWith unzip(rightEdge(x)), unzip(leftEdge(y)), correlate

them0nk

#Model 

@user.should have(1).error_on(:username) # Checks whether there is an error in username 
@user.errors[:username].should include("can't be blank")  # check for the error message 

#Rendering
response.should render_template(:index)

#Redirecting 
response.should redirect_to(movies_path)

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD