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.

You can not directly insert ruby code in javascript file. You need to pass some parameters by ajax. — Debadatt
– Debadatt, Commented Jul 23, 2013 at 12:03
I think you should rework on the solution to pass data as variable instead :) — Tzu ng
– Tzu ng, Commented Jul 23, 2013 at 12:04

Konstantin Rudy · Accepted Answer · 2013-07-23 12:12:53Z

8

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.

edited Jul 23, 2013 at 12:12

answered Jul 23, 2013 at 12:05

Konstantin Rudy

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MurifoX · Accepted Answer · 2013-07-23 12:03:25Z

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.

answered Jul 23, 2013 at 12:03

MurifoX

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Comments

Flak DiNenno · Accepted Answer · 2014-11-23 16:27:27Z

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 %>();

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