Not long ago [1], I wrote the DWScript JavaScript Smart-Linker did not eliminate unused virtual methods, well that limitation is now gone.
A virtual method that is never called, in its base class nor any of its subclasses, will now be eliminated.
In the small game Nickel Iron [2] which was used as illustration, that further reduces the generated output by almost 10% to just 92 kB “raw”, or 23 kB compressed. The gains come from not just the unused implementations being removed, but also a reduction in the size of the various VMTs.