Doubt about strings

Hi, this is my issue:

I have a variable, university, and for every time that the word ‘University’ appears, I want to replace it with a ‘U.’ to abreviate.
After that i want to reduce the quantity of characters to 25 but that isn’t an issue for me.
This is what i have yet:

if this.includes('University') 
then this.replace('University','U.');

  this.first(25);

Any help to fix the first part of the code will be well received.

this.sub! ‘University’, ‘U’

assuming you are doing this in a function