in i18n-js cannot generate a translation file per available locale when there are multiples namespace in 'only'

I am trying localisation in js file using i18n-js gem.

in i18n-js.yml

translations:
  - file: "app/assets/javascripts/i18n/%{locale}.js"
    only: ['cust_details', 'order_details']
I am trying to load only 'cust_details' and 'order_details' into translation file and split them per locale (i.e) create separate js translation file for each language with translations only for 'cust_details' and 'order_details' while avoiding loading of other keys.

I tried the following too :

translations:
- file: "public/javascripts/i18n/%{locale}.js"
  only: ['*.cust_details', '*.order_details']

Both the above methods return syntax errors in 'only' line.

When I try to add a single content/namespace this works fine. ex:

translations:
  - file: "public/javascripts/i18n/%{locale}.js"
    only: "cust_details"

The above code works

Thanks.