Friendly Elm (怖くないElm)

An introduction to Elm, spoken at #10 市ヶ谷Geek★Night「型のあるフロントエンドの世界〜フロントエンド・フロンティア〜」 http://ichigayageek.connpass.com/event/43149/

Transcript

1. 1 Friendly Elm 2016/11/04 Yosuke Torii
2. 2 怖くない Elm 2016/11/04 Yosuke Torii
3. 3 Who I am * Yosuke Torii * @jinjor * Works Applications Co., Ltd. * Contributor of Elm
4. 4 Who I am * Yosuke Torii * @jinjor * Works Applications Co., Ltd. * Contributor of Elm
5. 5 Introduction to Elm
6. 6 Q. How many folks have heard of Elm? Q. How many folks have written any piece of code in Elm?
7. 7 Q. How many folks have heard of Elm? 45 Q. How many folks have written any piece of code in Elm? 5
8. 8 Elm is a FP Language * Generates JavaScript * Static Typing * Everything is Immutable * Fast rendering via Virtual DOM
9. 9 Elm = Language + Framework VS No more JavaScript Fatigue!
10. 10 How strong is Elm's type? Strong Haskell Elm Scala Java TypeScript JavaScript Ruby Python Flow
11. 11 How strong is Elm's type? Strong Haskell Elm Scala Java TypeScript JavaScript Ruby Python Flow No Runtime Errors
12. 12 Experiencing Elm in Practice
13. 13 Making a seat arrangement app
14. 14 Lots of complex UIs! * Copy / Cut / Paste * Undo / Redo * Selecting * Dragging * Zooming * Searching * Context Menu * Clipboard * Keyboard Shortcuts * Auto Saving * Co-editing
15. 15 After several months... * Started using in our company (Still continuing development) * Open Source (WorksApplications/office-maker)
16. 16 Stats
17. 17 Stats 9,400 lines of Elm code
18. 18 Stats 9,400 lines of Elm code 0 runtime errors
19. 19 Refactoring with confidence * Regressions rarely happen * No fear with large/frequent changes * No untouchable code any more!
20. 20 But... it looks difficult to learn
21. 21 Elm is friendly for FP beginners ✓ FP for Front End developer ✗ Front End for FP programmer
22. 22 No need to learn Haskell VS * Monad and other terminologies from Category theory * Type classes in general use The most difficult parts do not exist in Elm
23. 23 Elm is getting even simpler 0.16 (2015/11) * More friendly compile error messages * Remove some record operations * Remove multi-way if 0.17 (2016/05) * Remove Signals (which was the most defficult) * Simplify main function 0.18 (2016/11) * More friendly compile error messages * Remove backticks * Remove [1..4] syntax * Remove primes in variable name
24. 24 Elm is getting even simpler 0.16 (2015/11) * More friendly compile error messages * Remove some record operations * Remove multi-way if 0.17 (2016/05) * Remove Signals (which was the most defficult) * Simplify main function 0.18 (2016/11) * More friendly compile error messages * Remove backticks * Remove [1..4] syntax * Remove primes in variable name
25. 25 Conclusion
26. 26 Elm is reliable Elm is easy to approach
27. 27 Thank you!