Map expression regex

Hi,

A simple one for the people that are expert in regex. I’m still learning it.
So, I have a key: notes that contains a value : “#IF:SLG-01-SL + some text here”

My goal is to always get the 9 characters after an ‘#IF:’
My expression I tried in the regex and works: ([#IF:])(.{0,12})
But how do I put it into a mapper?
First i check whether the notes contains ‘#IF:’ if thats true it goes to the path where i need to do the regex in the mapper

$notes.replace($notes, /([#IF:])(.{0,12})/g)
but now it gives the string of the regex.

Regards

Jens