I just tested out that exact code and it worked just fine. You don’t need PHP to interact with ACF’s javascript API. So accessing it with the global acf object like you are, should work fine.
The issue must be elsewhere, perhaps in your path to the script?
Can you log out other things successfully to verify that your script is enqueued properly?
Try logging out a string like: console.log('testing') does that work alright so we know the enqueue is correct?
