javascript - ECMAScript 6 child class prints with parents name -

when console.log(object) expect see name of object's class. seems rather unexpected child class carries name of parent.

"use strict";  class parent {   constructor () {   } } class child extends parent {   constructor () {     super();   } } class grandchild extends child {   constructor () {     super();   } }  var grandchild = new grandchild();  console.log(grandchild); // parent {} console.log(grandchild.constructor.name); // grandchild console.log(grandchild instanceof parent); // true console.log(grandchild instanceof child); // true console.log(json.stringify(grandchild)); // {} 

is intended behaviour? console.log that's messing up, or javascript consider instances of descendant class be, first , foremost, instance of root level class?

console not standard, can see in mdn entry. standard way class name of instance in es6 use instance.contructor.name. stated in the spec.