Note the omission of the 'function' keyword as in ES6 it is entirely optional
This seems a bit of a strange way to talk about this. I would instead have a sentence saying something like
Notice our use of the new "method definition" syntax for declaring methods for our class; we don't need the function keyword. This works in object literals, too.
This seems a bit of a strange way to talk about this. I would instead have a sentence saying something like