Leveling Up CIDER’s ClojureScript Support

Continuing the series on the notable changes in CIDER 2.0, let’s talk about ClojureScript - forever the trickier sibling in the CIDER family. I’ll start with a confession I’ve made before: I rarely use ClojureScript myself, which is a big part of why its support in CIDER has historically lagged behind Clojure’s. Every “State of CIDER” survey reminds me of this, usually in the comments section, occasionally in all caps. So in the 2.0 cycle I decided to stop feeling vaguely guilty about it and actually do something - across every layer of the stack: CIDER itself, cider-nrepl, and Piggieback. First, a strategic decision The most important ClojureScript change in CIDER 2.0 isn’t a feature - it’s a decision about what not to build. Some of CIDER’s most powerful tools (the debugger, enlighten, tracing, profiling) are deeply tied to JVM runtime introspection, and porting them to ClojureScript would be a massive effort with a poor cost/benefit ratio. Rather than keeping them in eternal “maybe…