Is there any way to get the unsatisfied variables / placeholder?

[chingjustwe]

Question

In my situation, users make an API call to render a template, while providing the necessary parameters.
There will be multiple templates, and the user will need to provide different parameters (a Map) for each template. If there are any variables in the template that are not satisfied, I would like to obtain the list and notify the user.

Is there any Pebble extension available for this purpose? Thank you.