Unexpected values in add-on configuration JSON payload #59

Hello,

I've encountered some unexpected JSON serialization behavior with add-on configuration data. This is best illustrated with an example.

Example

When a Primo admin uploads the following configuration JSON:

{
 "disableWhenAvailableOnline": true,
 "disableForJournals": false,
 "ignoreCopyright": false,
 "matchOn": {
   "oclc": true,
   "isbn": false,
   "issn": false,
   "lccn": false
 }
}

... the actual JSON that get passed to the add-on when the remote module is bootstrapped looks like this ¹:

{
  "disableWhenAvailableOnline" : "true",
  "disableForJournals" : "false",
  "ignoreCopyright" : "false",
  "matchOn" : "{oclc=true, isbn=false, issn=false, lccn=false}"
}

Issues

1. Boolean values are serialized as strings, which can be subtly pernicious in javascript if you're expecting boolean values.
2. Nested objects are serialized as "{key=value}" strings, which looks like the result of calling .toString() on a Map instance in Java.

Proposed next steps

I've already updated my add-on to handle these values, but I think it would be helpful to address the following:

1. Is this expected behavior?
2. If so, could we add some documentation for add-on developers indicating any potentially surprising JSON serialization behavior?

Thank you!