This document discusses CoffeeScript, a programming language that compiles to JavaScript. It provides an overview of CoffeeScript, highlighting its clarity, uniformity, and ease of translation to JavaScript. Key points include that CoffeeScript has alternative syntax that some find cleaner than JavaScript, compiles to readable JavaScript code, and is used by many popular Node.js modules and developers. Challenges of CoffeeScript like debugging and learning pains are also addressed.

1. Throw-down
Node.pgh Meetup

2. Nicholas McClay
UX Designer & Developer
@nickmcclay

3. There are a lot of opinions
about CoffeeScript

5. “You can take my JavaScript when you pry it from
“You can take my JavaScript when you pry it from
my cold dead hands!”
my cold dead hands!”

6. Let’s take a deep breath
and try and have an open
mind here...

7. What is ?
CoffeeScript is a small language that compiles into JavaScript
Usable for client-side and server-side applications (Node.js)
Has an opinionated alternative syntax for building JavaScript
applications

8. What is a Trans-compiling
Language?
Language?
Compile
.coffee .js

9. Pick your problem
“I want a better JavaScript!”
“I want functional
programming!”
“I want strict typing!”
Objective-J
“I want Objective-C!”
“I work at google!”
http://altjs.org/

10. Why should I care about
CoffeeScript?

11. Question: How many of
you use CoffeeScript?

12. Question: How many of
you have used a module
written in CoffeeScript?

13. Isaac Schleuter (maintainer of Node.js / NPM)
Node’s top contributors
TJ Holowaychuk (express, Jade, Mocha)
No Mikeal Rogers (Request)
No
No James Haliday "substack" (Browserify, dnode, Optimist)
No Guillermo Rauch (Socket.IO)
No
No Aaron Heckmann (Mongoose)
No
No Nathan Rajich "Too Tall Nate" (node-gyp)
No
Marak Squires (Hook.io, pdf.js, color.js)
No
Felix Geisendörfer
http://procbits.com/2012/05/18/why-do-all-the-great-node-js-develope
Tim Caswell (NVM)

14. And Yet...
Larger Node Community
Yes
Currently ranked 4th as the
most depended upon module in
NPM
More than Express! (just
barely)

15. Getting Started with
CoffeeScript

16. Learning CoffeeScript
http://coffeescript.codeschool.com/
http://arcturo.github.com/library/coffeescript/

17. Give it a try!
Install
sudo npm install -g coffee-script
Start the CoffeeScript REPL
coffee
Compile a .coffee file into equivalent .js
coffee --compile <path to js file>
Compile .coffee file when source changes
coffee --watch --compile <path to js file>
Compile and start file with Node.js
coffee --nodejs <path to node.js file>

18. Basic Node Connect Server

19. CoffeeScript Principles
1 - Clarity
2 - Uniformity
3 - Ease of
Translation
to JavaScript

20. Clarity

21. Significant White Space
1/2 to 1/3 compared to pure JavaScript

22. Keywords

23. Default Arguments

24. ((Parentheticals) Optional)

25. Uniformity
Everything is an expression!

26. Language Enhancements
Array Comprehension, Classes, and much more...

27. Fix some JavaScript pitfalls
http://bonsaiden.github.com/JavaScript-Garden/
this, null and undefined, prototype wackiness, goodbye
default global!

28. Ease of Translation to Javascript
The golden rule of CoffeeScript is: "It's just JavaScript"
The compiled output is readable and pretty-printed,
passes through JavaScript Lint without warnings

29. Learning Pains

30. CoffeeScript Misunderstandings
CoffeeScript is NOT a superset of JavaScript
CoffeeScript is compiled NOT interpreted at runtime
You must SHOULD learn JavaScript before using
CoffeeScript
Compiled CoffeeScript CAN be slower than pure JavaScript,
but really this usually isn’t an issue.

31. Mind the gap...

32. Mind the gap...

33. Punctuation Counts...

34. Punctuation Counts...
OR

35. CoffeeScript Pain Points?
Requires a compilation step (use file watcher or --watch)
Community is a subset of larger JavaScript community
Debugging...

36. CoffeeScript Debugging
Strategies

37. Mental Map Debugging
“You wanted to write it in CoffeeScript, you figure it out.”

38. Source Map Debugging
.js .map .coffee

39. WebStorm + CoffeeScript
http://www.youtube.com/watch?v=Sl1Uk3zT5Fg

40. Issue in WebStorm 6
CoffeeScript gives you :
WebStorm wants :
Manually adjusting the source map
reference makes it work...
http://youtrack.jetbrains.com/issue/WEB-7091

41. Even products that advertise CoffeeScript
support can have issues...

42. Add “await” and “defer” keywords for async

43. Thanks!
@nickmcclay