How to transform (simple) streaming XML in Node.js?

[oli9116]

I'm proxying an S3 call through my Node.js server and want to tweak just a couple of the returned XML values before proxying them. Except for those tweaks, I'd like to maintain the rest of each response, e.g. the response headers.I can of course gather the whole response first, parse the XML, transform it, and return it back, but for large responses that'll be both slow and memory-intensive. Is there a way I can achieve basically a \[code\]stream.pipe()\[/code\] but with maybe a transformation function?I've looked at sax-js, which can pipe but doesn't have any transform ability. Do I have to resort to listening to low-level parse events and generating and outputting the resulting XML myself?I've also looked at libxmljs which has a "push parser" and a higher-level DOM API, but it looks like I'd again have to listen to low-level parse events myself, plus I'm not sure I can stream the resulting XML out as it's generated.Is there any easier way than either of these two approaches? Thanks!P.S. The XML tweaks are simple: just removing a substring from some text elements.