Setting up indent-on-type in a treesit based major-mode

[Karan Ahlawat]

Hello,

Today I was using ruby-ts-mode and found out that it can indent some 
keywords as soon as they're typed out fully (example, when inside a case 
block). I'd love to implement such a feature in scala-ts-mode, so I 
looked at the source code, but could not see anything special it might 
be doing besides simple treesit indent setup.

So, how does it exactly achieve this indent-on-type behavior (I can see 
the matcher being called if I set treesit--indent-verbose to t), and how 
could I reproduce this in my own major-mode?

Thanks,

Karan