P1111111111 is valid and shouldn't be about iso8601-duration HOT 2 CLOSED

Same with PD or even just P

nesh> parse('PD')
{ weeks: 0,
  years: 0,
  months: 0,
  days: 0,
  hours: 0,
  minutes: 0,
  seconds: 0 }
nesh> parse('P')
{ weeks: 0,
  years: 0,
  months: 0,
  days: 0,
  hours: 0,
  minutes: 0,
  seconds: 0 }

These should throw IMO

from iso8601-duration.

I agree that there is a bug here. Or two:

• The current implementation tolerates any input that contains a valid duration.
• "P" is considered valid in itself.

=> Any string containing a "P" is considered a valid ISO duration, which is obviously not true (is "API" a valid duration?).

from iso8601-duration.