Comment by mike_hearn

The XSL:T equivalent for JSON is React.

Let's not romanticize XML. I wrote a whole app that used XSL:T about 25 years ago (it was a military contract and for some reason that required the use of an XML database, don't ask me). Yes it had some advantages over JSON but XSL:T was a total pain to work with at scale. It's a functional language, so you have to get into that mindset first. Then it's actually multiple functional languages composed together, so you have to learn XPath too, which is only a bit more friendly than regular expressions. The language is dominated by hacks working around the fact that it uses XML as its syntax. And there are (were?) no useful debuggers or other tooling. IIRC you didn't even have any equivalent of printf debugging. If you screwed up in some way you just got the wrong output.

Compared to that React is much better. The syntax is much cleaner and more appropriate, you can mix imperative and FP, you have proper debugging and profiling tools, and it supports incremental re-transform so it's actually useful for an interactive UI whereas XSL:T never was so you needed JS anyway.