The document describes GrooScript, a library and tool that converts Groovy code to JavaScript code. Some key points: - GrooScript is an Apache 2 licensed Java library and command line tool that converts Groovy to equivalent JavaScript code. - It supports many Groovy features like classes, closures, collections, and basic Groovy syntax but does not support all Java features or complex Groovy features. - The converted code works with the grooscript.js library and can be used in JavaScript projects or environments like Grails and Gradle.

1. grooscript in action
Jorge Franco - @jfrancoleza
v1.0.1

3. INFO
• Library (JAR)
• Groovy 2.0+ to javascript ECMA 5
• Apache 2 License
• Converted code needs grooscript.js
• Tools: gradle, grails, npm/bower

4. LINKS
• Website http://grooscript.org
• Documentation http://grooscript.org/doc.html
• Github https://github.com/chiquitinxx/grooscript
• Demos https://github.com/chiquitinxx/grooscript-demos
• Twitter @grooscript
• Try live! http://grooscript.org/conversions.html

5. CONVERT GROOVY CODE
Groovy / java code to javascript code
Groovy / java file to javascript file
Folder to folder or javascript file
List of files / folders to folder or javascript file
@Grab('org.grooscript:grooscript:1.0.1')
import org.grooscript.GrooScript
String result = GrooScript.convert '''
def sayHello = { println "Hello ${it}!" }
['Groovy','JavaScript','GrooScript'].each sayHello'''
println result

6. CONVERSION OPTIONS
• classPath - List of folders or jar’s to find dependencies. Before groovy code is converted to javascript,
that code have to be successfully compiled. For example: [''src/groovy'']
• customization - to each file to be converted, will be applied a groovy customization. For example you
can for example type check all the groovy classes to be converted with { -> ast(TypeChecked)}
• initialText / finalText - you can add test at the beginning or end of your converted javascript file.You
can add comments or javascript code. For example: ''//This code has been generated with grooscript''
• recursive - if you specify a folder with the source conversion option, by default will not convert files
inside folders.To convert recursive, just set to true
• mainContextScope - you can help the converted, specifying functions and variables that will be
availables in the main context of the javascript environment. For example: [''$'', ''window'',''myFunction'']
• addGsLib - you can add a grooscript js lib at the beginning of the converted file. For example you can
add grooscript.js to the result, and then you don’t have to worry about include that dependency in
javascript ''grooscript''

7. SUPPORT
SEE DOCUMENTATION
• groovy-core
• classes, numbers, lists, maps, sets, date, ranges, closures,
AST’s, (g)strings, operators, groovy truth, Expando,
categories, traits, beans, switch, metaprogramming, enum,
equals, multiple assignment, optional params, default
constructor, pointer methods, operator overload,
regular expressions, @Delegate, @Category, …

8. NOT SUPPORTED
SEE DOCUMENTATION
• Non groovy-core (json, builders, I/O, …)
• Java / GroovyTypes (Thread, LinkedHashMap, Stack, …)
• Super
• Methods with same name (overload), classes with same name
• Java 8 stuff not supported by groovy
• Module extensions, complex metaprogramming, groovy AST’s after
Semantic Phase

9. @GsNotConvert @GsNative
import org.grooscript.asts.GsNative
class Data {
@GsNative
def saySomething(some) {/*
console.log(some);
*/}
@GsNative
def five() {/*
return 5;
*/ 1 + 1 + 3
}
}
import org.grooscript.asts.GsNotConvert
@GsNotConvert
class ClassNotConvert {
def a
}
class A {
@GsNotConvert
def methodNoConvert() {
‘No!’
}
def hello() {
println ‘Hello!’
}
}

10. @GrabConfig(systemClassLoader = true)
@Grab(‘org.grooscript:grooscript:1.0.1’)
import org.grooscript.asts.PhantomJsTest
//Need phantomjs installed
System.setProperty(‘PHANTOMJS_HOME’, ‘path/to/phantomjs’)
@PhantomJsTest(url = 'http://beta.groovy-lang.org/')
void testCountLinks() {
def links = $('a')
assert links.size() > 40, "Number of links: ${links.size()}"
links.toArray().collect { it.toString() }.each { link ->
println link
}
}
testCountLinks()
PhantomJsTests

11. JAVASCRIPT LIBS
• grooscript.js (86 kb) (8 kb minified and gziped)
• grooscript.min.js (33 kb)
• grooscript-tools.js (14 kb)
(GQuery, HtmlBuilder, Observable)

12. given:
def result = HtmlBuilder.build {
body {
ul(class: 'list', id: 'mainList') {
2.times { number ->
li number + 'Hello!'
}
}
}
}
expect:
result == "<body><ul class='list' id=‘mainList'>
<li>0Hello!</li><li>1Hello!</li></ul></body>"
HtmlBuilder

13. import org.grooscript.jquery.GQueryImpl
def result = new Result()
def gQuery = new GQueryImpl()
gQuery.onReady {
gQuery.doRemoteCall(“${JSON_ADDRESS}”, 'GET', null, { res ->
gQuery('.result').html('OK')
result = res
}, {
result = 'FAIL!'
}, Result)
}
GQuery

14. given:
def result = []
Observable.from([1, 5, 9, 12, 3, 8]).
filter { it < 5 }.
map { 'H' * it }.
subscribe { event ->
result << event
}
expect:
result == ['H', 'HHH']
Observable

15. https://github.com/chiquitinxx/grooscript-gradle-plugin
http://grooscript.org/starting_gradle.html
http://grooscript.org/gradle/tasks.html

16. DEMO
https://github.com/chiquitinxx/books-demo

17. http://grooscript.org/grails-plugin/index.html
https://github.com/chiquitinxx/grails-grooscript
https://github.com/chiquitinxx/grooscript-grails3-plugin

18. var gs = require('grooscript');
bower install grooscript

19. WHY GROOSCRIPT?
• You have all the java tools and IDE’s
• Don’t repeat code in two languages
• Single development environment
• Don’t learn another “to Javascript” tool
• Static typed if you want to
• but… mainly… because is…

20. Concise
Readable
Expressive

21. @Component
class Counter implements Colorable {
Integer number
void init() {
number = null
}
void render() {
div(class: "widget bg-${randomColor()}") {
if (number) {
p 'Number of books'
em number.toString()
a(href:"#", class:"button",
onclick: 'bookPresenter.showBooks()') {
yield 'Show'
}
} else {
p 'Counting books...'
}
}
}
}

22. def start() {
def countries = loadCountries().
findAll { it.population > 100000}.
unique { it.alpha3Code }
countries.each { country ->
customSigma.addNode id: country.alpha3Code,
x: country.latlng[1], color: ‘purple’
}
countries.each { country ->
country.borders?.each { border ->
this.&hello(border)
}
}
updateNumberCountries countries.size()
customSigma.refresh()
}

23. server {
get('/') {
render Templates.applyTemplate('index.gtpl')
}
on('login') { data, socket ->
if (data.name && !socket.login) {
socket.login = data.name
socket.emit 'loginok', [name: data.name]
socket.broadcast.emit 'loginok', [name: data.name]
}
}
on('msg') { data, socket ->
if (data.msg && socket.login) {
socket.broadcast.emit 'msg', [msg: data.msg]
}
}
on('disconnect') { socket ->
if (socket.login) {
socket.broadcast.emit 'off', [name: socket.login]
}
}
}.start()

24. def plus2 = { it + 2 }
def times3 = { it * 3 }
def times3plus2 = plus2 << times3
assert times3plus2(3) == 11
def plus2times3 = times3 << plus2
assert plus2times3.curry(5)() == 21

25. NEXT
3

26. Q & A

27. Thank you!