Rails 3.1 insert ruby code in JavaScript file

Question

I am using Rails 3.2.12.
I would like to insert a ruby code in my asset JavaScript file:

function trim(string) { return string.replace(/(^\s+)|(\s+$)/g, ""); } function <%= controller_name %>() { ... } 

How can I do this?
Thanks in advance.

Answer 1

If variables you are going to pass are request-independent - then just give it a name *.js.erb.

For request-specific data (like controller name in your example) that's impossible. Javascript files are loaded independently from application requests and normally they are served as static assets by application server (apache, nginx). Thus if you want some custom script that is request-dependent put it inside your view template (.html.erb).

Also you can definitely proxy request to your js file through application (define it's route in routes.rb) but that will not be considered as good code.

Answer 2

I believe if you have a javascript file with the extension .js.erb or .js.coffee.erb, all the extensions would be parsed from right to left, thus your code should understand some erb tags inside it, before parsing the coffeescript and ultimately the js part.

Answer 3

I'm not sure why you would want to use the controller name when DEFINING your function, but if you really do, then

• change your JS file from a .js extension to .js.erb
• rename the file to match the correct route/action (i.e. create, update, destroy, et...) that it should respond to
• place it in your view folder

• modify/use: -link_to -button_to -form_tag -form_for with the remote: true attribute: e.g.
  <%= form_for(@article, remote: true) do |f| %>

  Find more information:

  1. here: http://edgeguides.rubyonrails.org/working_with_javascript_in_rails.html
  2. and here: http://www.alfajango.com/blog/rails-3-remote-links-and-forms-data-type-with-jquery/

ALTERNATIVELY,

You could predefine functions statically for each controller, e.g.:

 function Users(param1, param3...){ .... } function Friends(param1, param3...){ .... } function Likes(param1, param3...){ .... } function Posts(param1, param3...){ .... } 

then add an additional JavaScript statement to launch the appropriate function depending on which controller is being called, e.g.:

 <%= controller_name %>();