Hoist on my own PLV8 petard

I mentioned to a client that I was going to write a function they had asked me to write using PLPerl, because it has good dynamic string handling capabilities that make it a better fit for this particular task than PLPgsql. "Oh," said the client, "we don't do much Perl. But ever since you hooked us up with PLV8 we do everything in JavaScript. We all know that, and use it every day." So I'm now writing it in Javascript. Proof once again that no good deed goes unpunished. It remains to be seen if it's going to be quite such a good fit as Perl would be, but at least it will give me a thorough refresher in JS.