Not in the standard yet, but good incoming examples are decorators and private fields. They are not bad in all languages, but the way they are getting pushed in JS is awful.
String (capital "S") class.
Why don't you like Strings? All prototypes (Number, Array etc) have a capital letter.
I think that it is good. These functions for primitives (String, Number, etc) are good, one thing sometimes to call it, and also because of the prototype. Also, there is such thing as String.prototype.constructor and Number.prototype.constructor and so on, which I have used for parsing command-line arguments (to replace the default values with the user values, converted to the correct type).