Upgrading the package worked! Thank you so much. I'll update this thread if I notice any related bugs. Appreciate this.

Thanks @jan_blaha .
There is nothing wrong with script approach. I was just confirming.

d'oh ... on the subject of "..made a mistake" ... I'd created the asset with the helpers in, and referenced it as

{#asset common-handlers.js @encoding=utf8}

but ... I had a typo in the filename which was why it wasn't finding it. leaving this here so anyone else trying gets to search and learn from my stupidity ;)

Great. Happy to help.
Nice weekend for you too.