Berlin Node.js Meetup #3 - Js2coffee

Js2coffee helps you to migrate your projects to CoffeeScript and you can use http://js2coffee.org to learn CoffeeScript syntax.

It uses Mozilla's Narcissus interpreter to parse the JavaScript code and convert from the parsed Abstract Syntax Tree the generated CoffeeScript code.

Code snippest in my talk: https://gist.github.com/timaschew/9519475
Talk video: https://vimeo.com/88939283

Going further:
http://lisperator.net/uglifyjs/
http://esprima.org/
http://marijnhaverbeke.nl/blog/acorn.html
http://constellation.github.io/escodegen/demo/index.html

Transcript

1. js2coffee Anton Wilhelm | @timaschew
2. agenda history use cases online demo array appearance in v. 0.1.4 array appearance in v. 0.2.0 how it works abstract syntax tree builder class use cases Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew
3. js2coffee Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew - Rico Sta Cruz @rstacruz - written in CoffeeScript - first version June 2011 - last code change June 2012 - May 2013 Benjamin Lupton @balupton became a maintainer - my pull request in September 2013 ... I became a maintainer and then owner
4. demo Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew http://js2coffee.org code snippets: https://gist.github.com/timaschew/9519475
5. use cases Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew - learn CoffeeScript syntax - convert JavaScript to CoffeeScript - generate CoffeeScript
6. arrays in v. 0.1.4 Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew [ "foo", "bar", { y: 0, z: -1 }, [ 9, 8, 7, [ 71, 72, 73 ] ], "qux" ] ["foo", "bar", y: 0 z: -1 , [9, 8, 7, [71, 72, 73]], "qux"]
7. arrays in v. 0.2.0 Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew [ "foo", "bar", { y: 0, z: -1 }, [ 9, 8, 7, [ 71, 72, 73 ] ], "qux" ] [ "foo" "bar" { y: 0 z: -1 } [ 9 8 7 [ 71 72 73 ] ] "qux" ]
8. array appearance Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew - array have different looks: [] // empty array [oneElement] // one entry [ // more than one element foo bar baz ]
9. how it works? Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew - parse the code with Narcissus (Brendan Eich!) - return Abstract Syntax Tree (nodes) - check type of each node - identifier, number, function call, ... - run 2 steps (in series): - transform AST (Transformer) - existence check, inversible, returns - convert AST (Builder) - omit parentheses, function() {} to ->
10. abstract syntax tree Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew children: [ { type: 60, value: 'foo', lineno: 1, start: 0, end: 3, tokenizer: [Object], children: [] }, { type: 62, value: 'bar', lineno: 1, start: 6, end: 11, tokenizer: [Object], children: [] } ], type: 4, assignOp: null } foo = ‘bar‘ Identifier Literal AssignmentExpression
11. builder class Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew
12. ternary operator Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew Shortcut for first child
13. hidden line numbers Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew Hashtag Hashtag
14. array initialization 0.1.4 Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew
15. list node 0.1.4 Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew
16. array initialization 0.2.0 Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew
17. list node 0.2.0 Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew
18. use cases Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew - learn all CoffeeScript features - loops and comprehensions - classes and inheritance - issues - old narcisuss version - not the latest SpiderMonkey API - some switch statements fails - warnings / errors for things which CoffeeScript doesn‘t support - variable shadowing
19. Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew - JavaScript Parser API - Mozilla‘s Narcissus (even latest version is outdated, not maintained) - Mihai Bazon http://lisperator.net/uglifyjs/ - esprima, multipurpose analysis (Ariya Hidayat) - acorn, fastest JS parser (Marijn Haverbeke) - escodegen, AST → JS (Yusuke Suzuki) going further
20. THAT’S IT If you're into Node.js, CoffeeScript, NoSQL, Scrum get in touch, we're hiring ;) Twitter: @timaschew Source: http://github.com/js2coffee/js2coffee Web: http://js2coffee.org Soon: http://js2.coffee Node.js Berlin#3 | 2014-03-12 | Anton Wilhelm | @timaschew