[SugarCube 2]Allow Exceptions to Pass for Debugging

I'm not sure if exception handling is done by the story format or Twine,
but I'm using SugarCube 2.10.0 and compiling with the entwine utility (should be compatible with Twine 2.1).

Unfortunately, debugging Javascript is not very convenient right now inside a Twine story.
Any errors that occur bring up an alert that is not specific enough (does not point to line that's causing the problem).

It also unnecessarily eats up exceptions. If I

throw "some exception"

in the story Javascript, the alert will just say
"unknown error" rather than providing the text of the exception.

I imagine allowing debugging line-by-line might not be technically feasible, but allowing exceptions to pass through should be very dobale. Is there a reason why it's currently like this?