ClojureScript is a compiler for Clojure that generates JavaScript, allowing Clojure code to run in the browser and leverage the Google Closure Library. With strengths like interactive development, extensive libraries, and robust macros, it prioritizes stability and backward compatibility since its release in 2011. Although it offers a high-quality development experience, challenges remain in editor integration and working with external libraries.

1. Welcome to ClojureScript
Ikuru K

2. About me
- Work at Cybozu Startups, inc

3. Clojure?
- Programming language
- Lisp () () ()
- Hosted on the JVM, emits jvm bytecode
- Compiler, not an interpreter
- Fast!

4. ClojureScript?
- Clojure -> JavaScript Compiler
- Clojure code works on the browser!

5. Compiles this

6. To this!

7. Strength: Google Closure Library
- Pay only for the stuff you use
- unused stuff gets removed by Closure Compiler (later)
- Lot of good stuff
- Dom
- XhrIo
- Crypto
- UI Components
- And more...

8. Strength: Google Closure Compiler (advanced mode)
- Aggressive minification
- Dead code elimination
- Inlining
- ClojureScript emits code that can be
advance compiled

9. Strength: React wrappers
(+ React ImmutableDataStructures)
=> good
- Om, Reagent, Quiescent, Rum...

10. Strength: interactive dev via repl
- Figwheel + cljs-repl
- Hot load code into browser without
destroying state

11. Strength: Macros
- User extensible syntax without
changing core compiler
- Compile time calculation

12. Strength: Stability
- Backwards compatibility is high priority
- https://twitter.com/stuarthalloway/status/793614590781390852

13. Strength: Maturity
- First release = 2011

14. Strength: Runs on NodeJs
- https://github.com/anmonteiro/lumo

15. Strength: Targets React Native
- https://github.com/drapanjanas/re-natal

16. Interested?
1. Install leiningen (Clojure build tool)
2. $lein new figwheel (template)

17. Quick Demo

18. Resources
- ClojureScript for skeptics
- https://www.youtube.com/watch?v=gsffg5xxFQI
- Developing ClojureScript with Figwheel
- https://www.youtube.com/watch?v=j-kj2qwJa_E

19. Problems
- ‘Emacs harassment’
- First class dev experience coupled with good editor
integration
- Alternatives are growing, but still a challenge for a
newbie to learn the language+editor integration
- Integration with external libs
- Workaround with externs/Type inference
- cljsjs
- Situation getting much better these days

20. Enjoy!