This document discusses Single Page Applications (SPAs) and the JavaScript framework Backbone.js. It defines SPAs as web apps that handle interactions on the client-side without needing to reach the server. The document discusses why SPAs are useful for providing a fluid user experience but can increase code complexity. It introduces Backbone components like Models, Collections, Views and the Router that help manage this complexity by enforcing structure and separating concerns. Examples are provided of how to decompose user interfaces into Views and use Backbone to encapsulate state, add routing, and follow best practices like view-model associations and event-driven communication between components.

1. Single Page
Applications
Why and how of modern front-end development
through the lens of Backbone
www.dotnettoscana.org
#jsfullMassimo Iacolare
@iacoware
info@massimoiacolare.it
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2. Thanks to our sponsor
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3. SPA - Definition
“A Single Page Application is a web app
that fits on a single page with a goal of
providing a more fluid user experience”
from wikipedia
“... is a web app in which the majority of
interactions are handled on the page
without the need to reach a server ...”
me
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4. Context
Web Apps Web Sites
not
means javascript is on and graceful
degradation doesn’t matter
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5. Do you have an example?
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6. Do we need SPA?
Luca Mascaro - Better Software
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7. SPA - Definition
“A Single Page Application is a web app
in which the majority of interactions
are handled on the client without the
need to reach a server with a goal of
providing a more fluid user experience”
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8. Code complexity
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9. I’m a jQuery ninja
Why should I care?
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10. It starts very simple...
using objects to organize your jquery code
1. Load some content when a list item is
clicked
2. Hide the content for siblings list items
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11. Yay, Task done. Coffee time!
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12. Some time later you get a call...
• Url needs to be configurable
• We would like back button support
• Animations are so cool...
• We must mark the current item
• Let’s use a LightBox!
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13. using objects-to organize your jquery code
“Houston we might have a problem”
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14. Sad ninja
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15. What’s the problem?
• Application state kept on DOM
• State drives behavior. You’re coupling the logic
of your app to how it’s presented on the
screen
• They have different different reasons to
change
• DOM => appearance
• App => logic
• An App’s appearance hopefully will change
faster than its logic
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16. Our Goals
• Keep things simple (vs easy)
• Some kind of modularity (vs deps hell)
• Single Responsibility Principle
• Structure
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17. MV*, Here they comes
• Essentially they provide us with a pre-
defined path towards success our goals
• They enforce structure by giving us a set
of components (building blocks). Not to
be confused with widgets
• Different levels of prescriptiveness
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18. MV* - Who are they?
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19. Backbone Intro
• Created by J. Ashkenas
+coffeescript
+underscorejs
• Born on October 2010
• Only dependencies are
underscorejs + jQuery or
Zepto
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20. Tuesday, April 23, 13

21. Why Backbone?
• “Use only what you need” approach
• Based on jQuery. Reuse the skill you already
have
• Low learning curve, 1500 understandable LOC
included comments -> High ROI
• Huge community
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22. Backbone components
Model Collection
View
Template
HTML
Fragment
Router
contains
use
use
Events
use
Data
+
=
Template EngineBackbone
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23. Backbone.Events
• Publish and Subscribe events
• Inherited by all other components
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24. Backbone.Model
• Keep app state
• Persistent or
Transient
• Data access/
manipulation
through get() & set()
• REST friendly
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25. Backbone.Collection
• Sorted set of models
• Set manipulation
functions (provided by
underscorejs)
• Set manipulation
events (add, remove)
• REST friendly
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26. Backbone.View
• Render/manipulate a
DOM fragment
• Sits between a model/
collection and a DOM
fragment
• Observe models
• Handle DOM events
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27. Backbone.Router
• Enable the association
of an intermediate
app state as a URL
• You decide what
states should be
reachable as a URL
• It calls a callback
whenever a URL is
matched
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28. Backbone Progression
• Decompose UI into Views
• Encapsulate state in models
• Add routing to mark intermediate
states and support back button &
bookmarks.
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29. UI Decomposition
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30. Backbone tips &
tricks
aka lessons from the trenches
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31. Changes propagation
SearchView
save new
search
Propagate changes through state manipulation
add
Searches
SavedSearchesView
nope!
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32. View *-------1 Model
TweetsView TweetsCountView
TweetsCollection
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33. Everyone has a Base
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34. Don’t leave crumbs around
TweetsView
TweetView
TweetView
TweetView
Remove nested
views recursively to
avoid memory leaks
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35. Evolve & Adapt
TweetsView
TweetController
aka Glue Code
ComposeTweetView
Don’t feel constrained to use
only what Backbone provide.
Javascript is still there...
OMG
, it’s
not
from
Backbone!
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36. Precipitation pattern
View
Controller aka Glue Code
Model/Collection
Router
Follow the gravity
References Events
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37. Communication patterns
TrendsView EventsBus
Trends SearchController
tweets:search
tweets:search
Observer PubSub aka Mediator
aka EventBus
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38. Who uses it?
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39. Learn it :-)
• http://backbonefu.com/
• http://lostechies.com/derickbailey/category/
backbone/
• http://www.watchmecode.net/
• http://recipeswithbackbone.com/
• http://ricostacruz.com/backbone-patterns/
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40. Thanks!
#jsfull
www.dotnettoscana.org/javascript-full-immersion.aspx
Slides on:
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