I have researched how to send data from Rails to JavaScript in a Slim view template, and the most accepted method is to declare a Ruby section on the Slim template to get the data from the controller, and then declare a JavaScript section to store that data into a window variable, and then load the JavaScript pack that's going to use that data.
The data is needed to build a JavaScript snippet that will go in the <head> of our app.
Here's an example of what I'm doing (this is the app/views/layouts/_my-template.html.slim file):
ruby:
myDataFromRails = @my_data.to_json.html_safe
javascript:
window.myData = #{myDataFromRails};
- include_javascript_pack 'my-pack'
The problem with this method is that all the data coming from the Rails backend is available for anyone that inspects the code or types window.myData in the developer tools console, which is not ideal...
Another option will be to query the backend from the JavaScript snippet itself, using an HTTP request, but this doesn't look like an efficient way of getting the data from the backend.