The existing code had two issues: For one, e.g. calling a function that
returned a null interface reference mapped that to JS null, while querying an
object for a non-supported interface via `new css.uno.X...(y)` mapped that to
an "empty" JS object instead. (So checking for a non-null reference needed to
be done as either `x !=== null` or as `x.is()`, depending on context.) And for
another, while calling $is() on a non-"empty" object worked fine, it failed on
such an "empty" object (as the Embind internals of that object lacked the $$
property).
So change the querying mechanism from the `new css.uno.X...(y)` constructor to a
`css.uno.X....query(y)` function call syntax, which now returns JS null when
querying for a non-supported interface. (And drop the broken $is method.)
Change-Id: I8fa488ab2892423f2a461d9b72db47e1d4df3b8d
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/166255
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <stephan.bergmann@allotropia.de>
Stephan Bergmann
1c81f63e91