Is there a way of interpolation a string to access a JSON property or change variable names?

Question

maybe a noobie question.

I'm trying to use a dynamic string to interpolate with javascript variables and objects. Something like this:

let stringName = 'dinamicString'
this.dataService.subject.'stringName'.

I thought about using JSON.stringify() on the object, doing the string change, and parsing it back. But it looks more complicated than it should be and I would like to implement this dynamic string in other variables, not only in objects.