[CustomNPCs 1.12.2] How to make the block rotate constantly?

[mismoart]

I am a new to scripting. I’ll definitely deal with this, but now, unfortunately, there is no time. There are no sensible guides on this mod, which is why I decided to write here.  So, how to make a block that will rotate along the Y axis constantly? I suspect this can be done using a timer, but how exactly? And is it possible to add a function to stop this rotation?
I'm using ECMA language.

[DragonITA]

Have you tried Json files? And have you tried with Blockbench?

[mismoart]

7 minutes ago, DragonITA said:

Have you tried Json files? And have you tried with Blockbench?

 Thanks for quick answer! Hmm, but it is possible to do this using the script block from the mod, I suppose.

[DragonITA]

Sorry, but still dont am too advanced with Json and ItemBlocks rotation. I think you can see the Vanilla code and try to see how it work.