render_js

controller_1.rb

def show
  render_js do
    if result[:error]
      messenger_error(message: result[:error][:message])
    else
      messenger_success(message: 'Your message was sent successfully')
    end
    hide_modal
  end
end

controller_2.rb

def show
end

result.js

Messenger().post({
  "message":"Your message was sent successfully",
  "type":"success",
  "showCloseButton":true
  });
$('#modal').modal('hide');

show_2.js.erb

<% if result[:error] %>
  Messenger().post({
    "message":result[:error][:message],
    "type":"error",
    "showCloseButton":true
  });

<% else %>
  Messenger().post({
    "message":"Your message was sent successfully",
    "type":"success",
    "showCloseButton":true
  });

<% end %>

$('#modal').modal('hide');