Rails: access controller instance variable in CoffeeScript or JavaScript asset file

Question

In Rails 3.1 it is not possible to access controller instance variables in an asset js.erb or coffee.erb file using syntax such as <%= @foo %>, where @foo is set in the c

Answer 1

In the controller:

@foo_attr = { "data-foo-1" => 1, "data-foo-2" => 2 }

In the view (HAML):

#foo{@foo_attr}

In the CoffeeScript asset:

$("#foo").data("foo-1")
$("#foo").data("foo-2")