[throwaway54-762]

TLDR: v8 "sucks" (and doesn't support Unicode code points outside of the lowest ~64k characters).

Edit: v8 in general is pretty cool, but not supporting Unicode outside UCS-2 is pretty bad.

[marshray]

Most apps seem to "support" surrogate pairs by simply not being aware of them at all.

Good on the V8 developers for recognizing these conditions that their code didn't fully handle and refusing to muddle on through with broken processing.