CODEWITHSUNDEEP
javascriptruby-on-railsrubycoffeescript
scientiffic
scientiffic

Reputation: 9415

Access instance variable through coffeescript

I'm trying to access some ruby instance variables through a coffeescript file. At what point do instance variables become defined? For example, when I try the following:

$(window).load () ->    
 $('#s3-uploader').S3Uploader
    additional_data: {project_id: <%= @project.id %>, step_id: <%= @step.id %>, user_id: <%= current_user.id %>}

I get the error

Called id for nil, which would mistakenly be 4 -- if you really wanted the id of nil, use object_id
  (in /images.js.coffee.erb)

I know that @project should be defined, though, since I use it on the page when it's loaded. What am I doing wrong?

Upvotes: 0

Views: 489

Answers (1)

Amadan
Amadan

Reputation: 198324

Your CoffeeScript and your page are most likely in different views. Thus, having @project available when rendering your page says nothing about its availability when you're rendering your JavaScript. The easiest way to transfer this is to define a JavaScript variable inside your page view. For instance, if you're using Haml or Slim:

coffeescript:
  window.MyModule.project_id = #{ @project.id }

and then change your code to

additional_data: { project_id: window.MyModule.project_id, ... }

Upvotes: 1

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