Large Scale JavaScript Applications

Slides of my talk about large scale JS applications

Transcript

1. Large Scale JavaScript applications
2. @alexbeletsky http://beletsky.net http://github.com/alexanderbeletsky
3. Big Credits to: Addy Osmani Addy Osmani is a rebel JavaScript blogger, speaker and a UI Developer for AOL (yes, we're still around!). He is also a member of the jQuery [Bug Triage/Docs/Front-end] teams where he assists with bugs, documentation and developer evangelism. His recent open-source projects include TodoMVC, which helps developers compare JavaScript MVC frameworks. For more on Addy’s work, check out his official website AddyOsmani.com for tutorials and magazines such as .net for his thoughts and commentaries on the state of the web.
4. JavaScript apps evolution
5. Early JavaScript application • Mainly for web design • Copy/Paste pattern commonly used • Very poor browser support • Lack of “community” knowledge base • Low performace
6. Modern JavaScript application • AJAX era started • Adoption and respect by masses • Huge improvement on standard and vendors • Performance boosted • New web assembly language • Expertice & Best practices
7. Modern web app: GMail
8. Modern web app: Yandex Maps
9. Modern web app: Debitoor
10. “Modern web apps tend to be more (or equaly) complex on front end rather on back end”
11. In fact, JavaScript language is important... Front-end development could be complex...
12. What is Large scale app? “In my view, large-scale JavaScript apps are non- trivial applications requiring significant developer effort to maintain, where most heavy lifting of data manipulation and display falls to the browser.” - Addy Osmani
13. Complexity is handled by applying architectural approach
14. Patterns & Frameworks
15. Namespace Module Facade Mediator Observer
16. Namespace pattern “Namespacing is a technique employed to avoid collisions with other objects or variables in the global namespace” Goal: avoid names collision and provide facilities to organize blocks of functionality into easily managable groups
17. Namespace pattern implementation
18. Namespace Module Facade Mediator Observer
19. Module pattern “The module pattern is a popular design that pattern that encapsulates 'privacy', state and organization using closures” Goal: It provides a way of wrapping a mix of public and private methods and variables, protecting pieces from leaking into the global scope and accidentally colliding with another developer's interface
20. Module pattern implementation
21. Namespace Module Facade Mediator Observer
22. Facade pattern “ The facade pattern provides a convenient higher-level interface to a larger body of code, hiding its true underlying complexity. Think of it as simplifying the API being presented to other developers” Goal: to hide implementation-specific details about a body of functionality contained in individual modules. The implementation of a module can change without the clients really even knowing about it.
23. Facade pattern implementation
24. Facade pattern implementation Provides the open API for the rest of the application
25. Namespace Module Facade Mediator Observer
26. Mediator pattern “ The mediator is a behavioral design pattern that allows us to expose a unified interface through which the different parts of a system may communicate” Goal: promotes loose coupling by ensuring that instead of components referring to each other explicitly, their interaction is handled through this central point. This can help us decouple systems and improve the potential for component reusability.
27. Mediator pattern implementation
28. Facade pattern implementation Subscribe for particular event / Publish this event
29. Namespace Module Facade Mediator Observer
30. Observer pattern “ The Observer is a design pattern which allows an object (known as a subscriber) to watch another object (the publisher), where we provide a means for the subscriber and publisher form a listen and broadcast relationship” Goal: the promotion of loose coupling. Rather than single objects calling on the methods of other objects directly, they instead subscribe to a specific task or activity of another object and are notified when it occurs.
31. Observer pattern implementation https://gist.github.com/661855
32. Observer pattern implementation
33. RequireJS and AMD
34. RequireJS: file and module loader
35. RequreJS: Usage example
36. RequireJS: Main script
37. RequireJS uses Asynchronous Module Definition to load modules
38. AMD: module example
39. Putting thing together
40. Proposed Architecture Module Facade Mediator RequireJS AMD • Loosely coupled • Broken into independent modules • Flexible (framework agnostic)
41. Demo application
42. backbone-aura
43. Further reading: • Learning JavaScript Design Patterns http://addyosmani.com/resources/essentialjsdesignpatterns/book/ • Patterns For Large-Scale JavaScript Application Architecture http://addyosmani.com/largescalejavascript • Writing Modular JavaScript With AMD, CommonJS & ES Harmony http://addyosmani.com/writing-modular-js/ • Scalable JavaScript Application Architecture http://www.youtube.com/watch?v=vXjVFPosQHw&feature=youtu.be
44. Thank you. http://beletsky.net @alexbeletsky