UCS-16 is only used by programs which jumped the gun and implemented Unicode before it was all done. (It was 16 bits for awhile with Asian languages sharing code points so that the font in use determined whether the text was displayed as Chinese vs Japanese vs. etc). What Century was V8 written in that they thought UCS-16 was an acceptable thing to implement?
Good rule of thumb for implementers: get over it and use 32 bits internally. Always use UTF-8 when encoding into a byte stream. Add UTF-16 encoding if you must interface with archaic libraries.
Good rule of thumb for implementers: get over it and use 32 bits internally. Always use UTF-8 when encoding into a byte stream. Add UTF-16 encoding if you must interface with archaic libraries.