Question

Rails 3.2.8. In converting some of my JS functions over to CoffeeScript, I have come across several questions that say declaring a function like so:

@foo = (bar) ->

puts foo in the global namespace. But it doesn’t, because my function calls elsewhere in the application, especially ones that are in .js.erb files.

Here’s what does work:

foo = (bar) ->

window.foo = foo

With that, all my calls in .js.erb files work fine.

What is the reason that the @foo = notation doesn’t work as I am expecting it to? That would be a lot easier than having to remember to add an extra line to expose the function to the global namespace.

Answer 1

@foo translates to this.foo

foo translates to var foo

There is a big difference between the two of those.

---

For example:

bar = (baz) -> 
 @bar = 5
 lemon = @bar + baz

 @foo = (bar) ->
  lemon
 return @

Bar = new bar(12)

Translates to:

var Bar, bar;

bar = function(baz) {
  var lemon;
  this.bar = 5;
  lemon = this.bar + baz;
  this.foo = function(bar) {
    return lemon;
  };
  return this;
};

Bar = new bar(12);

See fiddle demo of generated code: http://jsfiddle.net/maniator/rXWw2/

Here is a link showing you the CoffeeScript and it’s generated code