Question

Why is re-frame implemented in .cljc files? Aren't ClojureScript files meant to be .cljs?

Answer

So tests can be run on both the JVM and the JS platforms, re-frame's implementation is mostly in .cljc files.

The trailing c in .cljc stands for common.

Necessary interop for each platform can be found in interop.clj (for the JVM) and interop.cljs (for JS).

See also: https://github.com/day8/re-frame-test