Types in Real Life

Practical approve to types in javascript

Transcript

1. Types in Real Life How to improve your dev workflow Sibelius Seraphini
2. Sibelius Seraphini @sibelius @sseraphini 2
3. - Motivation - Basics - Sum types - Generics - REST api study case - React - Redux - Utilities Outline 3
4. Type System in JS 4
5. - Less bugs - More maintainability - Type Driven Development Motivation 5
6. - Better tools support - Code completion - Refactor - Documentation - Jump to definition Motivation 6
7. - Types are set of values - string - 'a' | 'b' | 'c' | ... - number - 1 | 2 | 3 | ... - boolean - true | false - function - string -> boolean | ... - object - { a: string, b: number } | ... What are Types? 7
8. Typing a variable 8
9. Typing a function 9
10. Typing an object 10
11. Nominal Typing 11 - C++, Java, Swift
12. Structural Typing 12 - OCaml, Haskell, Elm
13. Typing an array 13
14. Sum/Union Type 14
15. Intersection Type 15
16. - How to type a function that can be used for any type of array (int[], string[], number[])? Generics 16
17. Generics 17
18. 18 Optional type
19. - type the input - api body payload - headers - query string Typing a REST API 19
20. - type the output (response) - Get a json output of a REST api - Transform json to types - https://transform.now.sh/json-to-flo w-types/ Typing a REST API 20
21. Typing a REST api 21
22. Typing a REST api 22
23. Typing a React Component 23
24. Typing a React Component (TS) 24
25. Typing a React Component 25
26. Typing a HOC 26
27. Typing Redux 27
28. Typing Redux 28
29. Typing Redux 29
30. Flow Type Utilities 30
31. TypeScript Utilities Mapped Types 31
32. TypeScript Utilities Conditional Typing 32
33. Resources 33 - https://github.com/entria/guidelines/tree/ master/flow - https://flow.org/en/docs/lang/ - https://www.typescriptlang.org/docs/ho me.html - https://github.com/fantasyland/fantasy-l and - https://github.com/gcanti/flow-static-land
34. Resources 34 - https://medium.com/javascript-scene/m aster-the-javascript-interview-what-is-fu nctional-programming-7f218c68b3a0 - https://medium.com/@matthiasak/state- of-the-union-js-d664bdbffd14 - https://mitpress.mit.edu/books/types-an d-programming-languages - https://github.com/niieani/typescript-vs-fl owtype
35. Resources 35 - https://transform.now.sh/json-to-flow-typ es/
36. I didn't mention 36 - More about Type Theory - Functional Programming - Types + Functional - Fantasy Land specs - Realworld problems and solutions
37. Sibelius