you should consider publishing/including sax-js via cljsjs instead.
Including the lib directly means that others are unlikely to see it and if something else in a CLJS builds also ends up using sax-js by other means they'll end up including sax-js multiple times in the build.
It may not be an issue in this case (or you just might not care about build size) but in general this pattern should be avoided.
Regards,
Thomas