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:

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