ExecJS lets you run JavaScript code from Ruby. It automatically picks the best runtime available to evaluate your JavaScript program, then returns the result to you as a Ruby object.

ExecJS supports these runtimes:

• therubyracer - Google V8 embedded within Ruby
• therubyrhino - Mozilla Rhino embedded within JRuby
• Node.js
• Apple JavaScriptCore - Included with Mac OS X
• Microsoft Windows Script Host (JScript)

A short example:

require "execjs"
ExecJS.eval "'red yellow blue'.split(' ')"
# => ["red", "yellow", "blue"]

A longer example, demonstrating how to invoke the CoffeeScript compiler:

require "execjs"
require "open-uri"
source = open("http://jashkenas.github.com/coffee-script/extras/coffee-script.js").read

context = ExecJS.compile(source)
context.call("CoffeeScript.compile", "square = (x) -> x * x", :bare => true)
# => "var square;\nsquare = function(x) {\n  return x * x;\n};"

$ gem install execjs

Copyright (c) 2011 Sam Stephenson and Josh Peek.

Released under the MIT license. See LICENSE for details.