Talk @ JCConf 2018

1. Modern ClojureScript
cataska @ JCConf 2018

2. About Me
/ / /

3. What is ClojureScript ?
ClojureScript is a compiler for
Clojure that targets JavaScript.

4. Why Clojure?

5. Clojure
• LISP
• Dynamically typed
• Functional
• Immutability
• Laziness
• Hosted on JVM

6. Rich Hickey
Creator of Clojure

7. LISP

8. John McCarthy
Father of AI and LISP

9. Parentheses

11. Syntax

12. Why JavaScript?

14. Oracle Nashorn

15. Clojure rocks,
and JavaScript reaches.
— Rich Hickey

18. Data Types

19. Data Types (cont.)

20. Functions

21. Composition

22. Currying

23. Macros

24. LISP is a programmable
programming language.
— John Foderaro

25. parser & lexer
1 + 2 * 3
Evaluator
+
1 *
2 3
0111
non-LISP

26. parser & lexer
1 + 2 * 3
Evaluator
+
1 *
2 3
0111
non-LISP
Not accessible in program

27. Reader
(+ 1 (* 2 3))
Evaluator
+
1 *
2 3
7
ClojureScript
Totally accessible in program

28. Unia Lubelska by Jan Matejko

31. Reader
(infix (1 + 2))
1
+ 2
infix
Macro Expander
+
1 2
Evaluator
3

32. Immutability

34. Laziness
Mostly

35. Infinite and lazy sequence

36. Interactive Development
a.k.a. REPL

37. REPL
(Loop (Print (Evaluate (Read))))

38. > Starting REPL

39. > Connected

40. > Test your ideas

41. > Browser-connected REPL

42. core.async

43. core.async
• Based on CSP
• Asynchronous programming
• Library for Clojure and ClojureScript
• Channel-based concurrency
• Implemented using macro

45. Channel

46. Go blocks: lightweight thread

47. Go blocks

48. Interoperability

49. JS Interop

51. Google Closure Tools

52. • Compiles into compact, high-performance code.
Google Closure Tools

53. • Compiles into compact, high-performance code.
• Minification and tree shaking.
Google Closure Tools

54. • Compiles into compact, high-performance code.
• Minification and tree shaking.
• Well-tested, modular, and cross-browser library.
Google Closure Tools

55. • Compiles into compact, high-performance code.
• Minification and tree shaking.
• Well-tested, modular, and cross-browser library.
• Used by Gmail, Google Maps and Google Docs.
Google Closure Tools

56. • Compiles into compact, high-performance code.
• Minification and tree shaking.
• Well-tested, modular, and cross-browser library.
• Used by Gmail, Google Maps and Google Docs.
• Solid foundation for ClojureScript.
Google Closure Tools

57. Using Closure Library

58. Figwheel

60. Figwheel
• Live code reloading
• Static file server
• Live CSS reloading
• Heads up display
• Won’t load code that is
generating warnings

61. Devcards

62. Devcards
• Interactively develop
component
• Browse component library
• View different state of each
component

63. Prior to Storybook

64. shadow-cljs

65. shadow-cljs
• Live Reload (CLJS + CSS)
• CLJS REPL
• Importing npm modules
• Good configuration defaults

66. Inventing on Principle
Bret Victor

67. Creators need an immediate connection to what they create.

68. Editors

69. Front-End Frameworks

71. Interface to React
• Om
• Reagent
• Rum

72. App

73. Desktop

74. Mobile

75. Oracle JDK new license

76. ClojureScript w/o JVM

77. Lumo

78. Planck

80. s/isomorphic/universal/g
React PR #4041

82. —

83. Thank you