How do you create javascript functions that are available project-wide in Ruby on Rails?

Question

I put the following function in my application.js:

function test() {
  alert("See Me")
}

classrooms/_new_small.html.haml:

:javascript
  alert('test');
  test();

In my application.html.haml I'm using the following:

= javascript_include_tag 'application'

I'm getting a test is not defined error in my firebug console. Isn't the test function supposed to be available project-wide because its in the application.js file? Thanks

edit: I'm rendering the page via javascript. Would that affect it?

$('#test_container').html("<%= escape_javascript(render :partial => 'classrooms/new_small') %>");

Answer 1

Assuming you are using asset pipeline & coffeescript: Don't write code in application.js

In order to keep clean structure, create a folder (eg: application) in app/assets/javascripts

then require it in your application.js

//= require jquery
//= require jquery_ujs

//= require_tree ./application

Create a coffee file (eg: app/assets/javascripts/application/my_feature.js.coffee

@test = ->
  alert('Hello world')

Coffee output:

(function() {

  this.test = function() {
    return alert('Hello world');
  };

}).call(this);

It's preferable to use namespaces:

@myGreatFeature =
  test: ->
    alert('Hello world')

or according to the coffeescript FAQ, you could write

namespace = (target, name, block) ->
  [target, name, block] = [(if typeof exports isnt 'undefined' then exports else window), arguments...] if arguments.length < 3
  top    = target
  target = target[item] or= {} for item in name.split '.'
  block target, top

namespace 'myGreatFeature', (exports) ->
  exports.test = ->
    alert('Hello world')

then you can call myGreatFeature.test() everywhere

Answer 2

Simple solution, remove escape_javascript, but it's dangerous see Why escape_javascript before rendering a partial? . Currently you want to execute

$('#test_container').html("<script>
//<![CDATA[
 alert('test');
 test();
//]]>
</script>

which is converted into

$('#test_container').html("<script>\n  //<![CDATA[\n    alert(\'test\');\n    test();\n  //]]>\n<\/script>\n");

How do i solve this problem ?

i will include project_wide.js in app/assets/javascripts/ and then tell application.js to include my file .

//= require project_wide

Be sure to put the above line after

//= require jquery
//= require jquery_ujs

Now, whatever i put in app/assets/javascripts/project_wide.js it will shamelessly appear in whole project except the files which are in public/ folder . In this file, i will put everything which i want to execute .

Follow common practice

Currently,you are adding javascript directly inside classrooms/_new_small.html.haml which is uncommon. Mostly , rails developer put such things in assets/javascripts/*.js or call content_for :javascript_custom block in views , which is added in layout file by yield :javascript_custom