Free standing function in coffeescript in Rails 3.2.8 - ruby-on-rails

Question

I've recently started using coffeescript in my rails projects pretty heavily.
I'm curious how you make a free standing function. So if I do:
foo = ->
alert("hello world")
That compiles to
(function() {
var foo;
foo = function() {
return alert("hello world");
};
}).call(this);
How do I make it compile to
var foo;
foo = function(){
return alert("hello world");
}
I want to be able to call use link_to_function "foo"

Answer 1

There are actually several ways you can accomplish this (one way already given in the comments).
Compile without the closure wrapper
This will expose all functions to the outer scope. This may be an option if you are using a lighterweight framework where you can control of the build process. I'm not sure you would be able to within the context of the asset pipeline but works great in the context of a small sinatra app.
coffee -b myfile.coffee
Attach to a global object
If you know you are targeting a specific runtime, like the browser you can use the global window object.
window.foo = -> alert("hello world")
This is the same effect as the solution in the comments since the target is a Rails environment. But using # which is sugar for this. will attach it to whatever the scope of this is at the moment. Assuming the function is not being defined in a callback or an internal object with a bound context, it would likely be the window object.
#foo = -> alert("hello world")
Better would be to create your own namespace and attach that way:
Mine ||= {}
Mine.foo = -> alert("hello world")
#Mine = Mine
CoffeeScript classes
Or use CoffeeScript's class syntax to do the same by attaching to the prototype itself:
class #Mine
#foo: -> alert("hello world") # called as Mine.foo() (notice the # declaration)
In our rails applications we typically have an asset that defines the namespace, aka a file at app/assets/javascripts titled mine.coffee:
window.Mine ||= {}
and then in other files we can require that namespace:
#= require mine
class Mine.MyOtherThing
#foo: -> alert("hello world")