If you’re trying to learn Clojure(Script) and Om, perhaps using the otherwise fantastic Om Basic Tutorial, you may (if you skipped certain steps of the tutorial) run into the following error:
If you do, you’re likely running one of the older versions of Om that are on the main clojars repositories, as opposed to the current version (as of February 1st), 0.8.6.
To fix this error, just update your
project.clj file from referencing
[om "0.7.X"] to referencing
[org.omcljs/om "0.8.6"]. Make sure to re-start your REPL.