The new Rails 3.1 asset pipeline is really nice, but since all CoffeeScript (or JavaScript) files get melded down into a single file that is included in every page, it raises this question:
How do I limit the execution of my script to a particular controller or action? Is there a way within my CoffeeScript to know which controller and action was used during the request so that I can put conditional statements in my script?
Or am I approaching this the wrong way altogether?
The new Rails 3.1 asset pipeline is really nice, but since all CoffeeScript (or JavaScript) files get melded down into a single file that is included in every page, it raises this question:
How do I limit the execution of my script to a particular controller or action? Is there a way within my CoffeeScript to know which controller and action was used during the request so that I can put conditional statements in my script?
Or am I approaching this the wrong way altogether?
Share Improve this question asked May 26, 2011 at 11:27 adamjcooperadamjcooper 1,1411 gold badge12 silver badges24 bronze badges 2- 1 Possible duplicate of stackoverflow./questions/6133235/…; see my answer there. – Trevor Burnham Commented May 26, 2011 at 16:10
- Thanks Trevor; making script conditional on the presence of an element or a particular CSS class on the body tag seems like a nice approach. – adamjcooper Commented May 26, 2011 at 18:54
5 Answers
Reset to default 9Trevor Burnham answers this question nicely here: How do I associate a CoffeeScript file with a view?
He says:
There are two mon approaches:
Make behavior conditional on the presence of a particular element. For instance, code to run a signup sheet should be prefaced with something like
if $('#signup').length > 0Make behavior conditional on a class on the
bodyelement. You can set the body class using ERB. This is often desirable for stylesheets as well. The code would be something like
if $('body').hasClass 'user'
And if you're interested in CoffeeScript, Trevor is working on a book that looks to be very good: http://pragprog./titles/tbcoffee/coffeescript
One way to restrict coffeescript to a particular view is to make a custom sprockets file for the javascript in question, similar in format to application.js. Say you call it extras.js.
//= require my_code.js.coffee
Then use javascript_include_tag "extras" to include that code in the views you want, either by making a custom layout for those views, or by using content_for()
BTW, your question stated that the rails pipeline forces you to put all your js assets in one file. That's not true. That's efficient often to avoid multiple round trips, but you can have multiple sprocket files.
Why not to put the javascript for the particular controller as a view on this controller (as they correspond there if are so specific)?
If they are general enaugh you can mark your view with classes, ids or data (html5) and make your javascript look for that (so you can reuse your code).
what i normally do is to have a yield :js under the javascripts in my layout and when I need a specific script it, I load it directly from my view with:
content_for :js do
javascript_include_tag "myscript"
end
If you are using the gon gem for your vars in coffee script you can use this pattern:
Put a flag for every action in the controller:
def index
@gps_coords = GpsCoord.all
# Flag for the CoffeeScript to decide which part to run
gon.index = true;
end
def show
@gps_coord = GpsCoord.find(params[:id])
gon.lat = @gps_coord.latitude
gon.lon = @gps_coord.longitude
gon.show = true;
end
In the correlating coffee script use those flags to distiguish between the both actions:
# index action?
if gon.index?
first_coord = gon.gps_coords[0]
map.setView([first_coord.latitude, first_coord.longitude], 15);
# show action?
if gon.show?
map.setView([gon.lat, gon.lon], 15);