Here, I'll document some code I found to be much easier or better to do in an appscripts context with modern Javascript.
You have a string that represents a range speciation using a1Notation. You need to get the starting row number. Or you need to get the last column. Or you need to get all of those things. You'd like to do it in a way that can be reused. And you wonder if some of the new syntax features makes this interesting.
Let's go over the skeleton of the function first: