Nice! Thus, to map this replacement to a vim command (using a vim with perl support):

:command FixCommas perl $s=join(qq{\n},$curbuf->Get(0 .. $curbuf->Coun
+t()));$s =~ s#^((?:[^/\n]|/(?!/))*),((?:\s*|//.*$|/\*(?:[^*]|\*(?!/))
+*\*/)*\s*[}\]])#$1$2#mg; $curbuf->Set(0,0,split(qq{\n},$s));
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(Tried it as a simple :%!perl -pi -e at first, but vim hated the # characters.)