Using Ruby Variable in Script Tag

Question

I'm defining an intercom event in my rails controller like so:

object_controller.rb

@object.save
@intercom_event = 'object-saved'

In a partial that exists in my application.html.erb I am trying to run this script:

<script>
 Intercom('trackEvent', '<%= @intercom_event %>');
</script>

The script runs and sends the event up to Intercom like its supposed to. I thought I am placing the ruby variable into the <script> tag correctly except the output for @intercom_event is: <%= @intercom_event %> when it should be: object-saved.

Additionally if I were to wrap this <script> tag in an if statement (so that it doesn't send an event every time the page is reloaded) like so:

<% if @intercom_event.present? %>
 <script>
 Intercom('trackEvent', '<%= @intercom_event %>');
 </script>
<% end %>

It ignores the script altogether, even when @intercom_event is defined.

Answer 1

Got it to work by looking to see if the params is present instead of the @intercom_event variable

<% if params[:intercom].present? %>
 <script>
 Intercom('trackEvent', '<%= params[:intercom] %>');
 </script>
<% end %>

Answer 2

You're on the right track:

<%- if @intercom_event.present? -%>
 <%= javscript_tag do -%>
 Intercom('trackEvent', '<%=j @intercom_event %>');
 <%- end -%>
<%- end -%>

The j method escapes for JavaScript context like the companion method h escapes for HTML. This is important to avoid scripting errors.

For more complicated structures, @intercom_event.to_json would give you a JavaScript compatible representation.

• Reuben: Hmm still not sending when wrapped in a <%- if @intercom_event.present? -%> tag. When I removed the if statement it's now sending nothing up to intercom. I wonder why the variable defined in the controller isn't being seen in the view file
• tadman: Controller instance variables are automatically propagated down to the view level. Are you sure you're hitting the right action? Always check log/development.log.