Variables from external javascript file seem to be internally cast to string


I have a function in an external javascript file that returns an object containing a number of system parameters. These are of different type (int/bool/string).

When I reference these object properties in the serverless.yml is appears to internally cast them all to a string which then causes my deploy to fail as certain parameters are expecting specific data types.


  logRetentionInDays: ${file(internal_params.js).log_ttl-days}

log_ttl-days is an integer (30) in the object returned by internal_params.js, however I get this error during deploy:

  Serverless Error ---------------------------------------
  logRetentionInDays should be an integer over 0

Is this expected behaviour? What can I do to resolve/mitigate this issue?