Slides of the talk given at MeetJS Summit (http://summit.meetjs.pl). The TreeHugger playground can be found here: http://ajaxorg.github.com/treehugger/test.html

1. Avoiding JavaScript Pitfalls
Through Tree Hugging
Zef Hemel (@zef)

3. JavaScript Developer

4. http://c9.io

5. we’re building
#1 JavaScript IDE

7. ~400,000

12. Iterating using undeclared variable

14. Warning: you are in an anonymous inner function with its
own “this” pointer -- ya sure this is what you mean?

16. Did you mean “length”?

17. How?

18. Unleash the
awesome power of...

19. tatic

20. X tatic

21. program analysis

22. What
can you do with it?

24. code outlines
code completion (intellisense)
code navigation
...

25. Parse
Analyze

26. Code Parser AST

27. Abstract Syntax Tree
Op
a * 10 Parser “*” Var Num
“a” “10”

28. Zeon Narcissus
UglifyJS
language.js
Esprima

29. performance (speed/memory)
AST datastructure
traversal tools

30. i fi c
ec
p
performance (speed/memory)
s
i pt
r
AST datastructure
S c
v a traversal tools
Ja

31. treehugger.js

32. “The JQuery of AST analysis.”

33. Standard AST Datastructure

34. Standard Traversals
+
Pattern Matching

35. Op
a * 10 “*” Var Num
“a” “10”

36. Op
Op("*", Var("a"),
“*” Var Num Num("10"))
“a” “10”

37. Op
ATerm
Op("*", Var("a"),
“*” Var Num Num("10"))
“a” “10”

38. Constructors Var(_)
Lists [_, _]
Strings "hello"
Placeholders x

40. http://github.com/ajaxorg/treehugger

47. http://github.com/ajaxorg/treehugger
http://c9.io @zef @cloud9ide