An article: http://maksimivanov.com/posts/static-type-checking-js Here we discuss the Javascript type system, why you might want to add static type checking on top of it and how to do it using Flow.

2. What, why and how
Static Type Checking

3. 3
Hi, I’m Maksim

4. 4

5. 5
Javascript has no types

6. 6
● Dynamic
● Weakly typed
● Loosely typed
● Unityped
● Untyped
Javascript is

7. 7
● Dynamic
● Weakly typed
● Loosely typed
● Unityped
● Untyped
Javascript is

8. 8
● Dynamic
● Weakly typed
● Loosely typed
● Unityped
● Untyped
Javascript is

9. 9
● Dynamic
● Weakly typed
● Loosely typed
● Unityped
● Untyped
Javascript is

10. 10
● Dynamic
● Weakly typed
● Loosely typed
● Unityped
● Untyped
Javascript is

11. 11
A type system is a tractable syntactic method
for proving the absence of certain program
behaviors by classifying phrases according
to the kinds of values they compute.

12. 12

13. 13
Dynamic nature of Javascript

14. 14
● Problem of complexity
● Separating by units
● Spaces in between
Why do we need static type checking

15. 15
● Problem of complexity
● Separating by units
● Spaces in between
Why do we need static type checking

16. 16
● Problem of complexity
● Separating by units
● Spaces in between
Why do we need static type checking

17. 17
PropTypes

18. 18

19. 19
Static Type Checking

20. 20

21. 21
● Catch errors early
● Type Inference
● Rich type system
Benefits

22. 22
● Catch errors early
● Type inference
● Rich type system
Benefits

23. 23
● Catch errors early
● Type inference
● Rich type system
Benefits

24. 24
● Literal types
● Union types
● Nominal types
● Structural types
Rich Type System

25. 25
● Literal types
● Union types
● Nominal types
● Structural types
Rich Type System

26. 26
● Literal types
● Union types
● Nominal types
● Structural types
Rich Type System

27. 27
● Literal types
● Union types
● Nominal types
● Structural types
Rich Type System

28. 28
● Literal types
● Union types
● Nominal types
● Structural types
Rich Type System

29. 29
● Define contracts – manage complexity
Final thoughts

30. 30
● Define contracts – manage complexity
● Get fast feedback
Final thoughts

31. 31
● Define contracts – manage complexity
● Get fast feedback
● Get smart suggestions from editor
Final thoughts

32. 32
● Define contracts – manage complexity
● Get fast feedback
● Get smart suggestions from editor
● More confidence when refactoring/changing
code
Final thoughts

33. 33
● Define contracts – manage complexity
● Get fast feedback
● Get smart suggestions from editor
● More confidence when refactoring/changing
code
● It will push you to better code design
Final thoughts

34. 34
● Should have good architecture first
Not a silver bullet

35. 35
● Should have good architecture first
● Not a substitute for tests
Not a silver bullet

36. 36
● Should have good architecture first
● Not a substitute for tests
● It adds some noise
Not a silver bullet

37. 37
● Should have good architecture first
● Not a substitute for tests
● It adds some noise
● Your team should know how to work with it
Not a silver bullet

38. 38

39. 39
Thank You!
@satansdeer
maksimivanov.com