Design Patterns

Transcript

1. Design Patterns Ruby Conf. Nigeria

2. ❖ Software Developer ❖ Consultant at Auth0 ❖ Open Sourcerer

   ❖ Self-Acclaimed Developer Evangelist ❖ Community Builder ❖ Jollof Rice Ambassador ❖ Google Developer Expert ❖ Homeless Man

3. @unicodeveloper - GitHub - Twitter

4. ...When no design pattern is involved.

5. None

6. ...After you involve design patterns.

7. None

8. ..A few things to note, thou developer

9. 1. Design patterns are not a silver bullet to all

   your problems.

10. 2. Design patterns was made for man, not man for

    design patterns.

11. 3. They can prove to be a savior, or else

    they can make you & your code a mess.

12. Design Patterns Grouped 1 2 ❖ Behavioral ❖ Creational ❖

    Structural

13. Behavioral Design Patterns 1 3 ❖ Mediator ❖ Observer ❖

    Strategy ❖ Visitor ❖ Iterator ❖ Command

14. Creational Design Patterns 1 4 ❖ Builder ❖ Prototype ❖

    Singleton ❖ Factory ❖ Abstract Factory

15. Structural Design Patterns 1 5 ❖ Facade ❖ Composite ❖

    Decorator ❖ Flyweight ❖ Adapter ❖ Bridge

16. ..Know JavaScript? I’ll use it as an example to explain

    the common design patterns that you should know & take advantage of in your codebase.

17. Singleton Pattern

18. Goals 1. Ensure that only one instance of a class

    is created. 2. Provide a global point of access to the object.

19. Singleton 1 9

20. Singleton 2 0 What makes the Singleton is the global

    access to the instance.

21. Prototype Pattern

22. Goals 1. Specify the kind of objects to create using

    prototypical instance. 2. Create new objects by copying this prototype

23. Prototype 2 3

24. Prototype 2 4

25. Command Pattern

26. Goals 1. Encapsulate the request in an object 2. Allow

    the parameterization of clients with different requests.

27. Command 2 7

28. Command 2 8 What if the core API of carManager

    changed? What happens?

29. Facade Pattern

30. Goals 1. Outward appearance to the world which hides a

    different reality. 2. Simpler public interface to avoid calling many internal methods to get some behavior working. 3. Ability to directly interact with subsystems in a way that can be less prone to accessing it directly.

31. Facade 3 1

32. Facade 3 2 JQuery’s document.ready() function is being powered by

    bindReady()

33. Factory Pattern

34. Goals 1. Creates objects without exposing the instantiation logic to

    the client. 2. Refer to newly created object through a common interface.

35. Factory 3 5

36. Factory 3 6

37. The Mixin Pattern

38. Goals 1. Allow objects to borrow functionality with a minimal

    amount of complexity.

39. Mixin 3 9

40. Mixin 4 0

41. Decorator Pattern

42. Goals 1. Similar to Mixins. Aim to promote code reuse

    2. Offer ability to add behaviour to existing classes in a system dynamically.

43. Decorator 4 3 Simple Use case

44. Decorator 4 4

45. Decorator 4 5 Decorating objects with multiple decorators

46. Module Pattern

47. Goals 1. Emulate the concept of classes. 2. Shield particular

    parts from global scope and make everything simple.

48. Module 4 8

49. Module 4 9

50. Observer Pattern

51. Goals 1. Define a one to many dependency between objects

    so that when one object changes state, all its dependents are notified and updated automatically.

52. Observer 5 2

53. Observer 5 3

54. Observer 5 4

55. Observer 5 5

56. Observer 5 6

57. Observer 5 7

58. Learning Resource http://www.oodesign.com/observer-pattern.html https://addyosmani.com/resources/essentialjsdes ignpatterns/book/

59. Thank You!