Debugging advanced queries tips (console.log or other approaches)

I’m trying to experiment my way around understanding the advanced queries and I am struggling how to do simple console debug statements. One approach I am trying to to is to implement is a as a rule, but no cigar, any ideas of how to do something like this:

:rules [ 
  [(log ?msg)
    [(js/console.log ?msg)]

But is just gives
```instrument.js:191 [frontend.ui] {:exception #error {:message “Unknown predicate 'js/console.log in [(js/console.log "hello")]”, :data {:error :query/where, :form [(js/console.log “hello”)], :var js/console.log}}````

Any ideas?

found some debugging tips here:

also learned just today that not all clojure(script) functions can be used as predicates – same page has a link to a list of functions that can.