Can derived classes have static get methods?

Update 2, added Gist:

Question: Can derived classes have static get methods?
3 files here, with attempted use of static get method in a derived class. It works correctly when accessed inside the class' .es6 file, but doesn't when imported for tests.

I'm just getting my head around ES6 class syntax, but am strong/comfortable in ES5 prototypal inheritance. I'm working on a set of tree data structures. Using Babel.

I have a derived class, RBTree: (see code below)

I want RBTree to have a static get method, that simply serves as a pointer/property to a null node I have already created. Say I have imported that node from another file, and it is called NULL_POINTER.

How do I get this static get method to return NULL_POINTER?

When I import it and try to access like so above, .null returns undefined.

I also have tried modifying RBTree outside of the class expression (RBTree.nullPointer = //...), which does not work.

Update 1:
Renamed some things. Code updated to reflect naming. I have a working implementation of my original test spike. Here are the relevant files:

RBTree.es6

import {NULL_POINTER} from 'file/with/null/pointer'
export const _NULL_SENTINEL = new RBNode()// constructs the null node
export class RBTree extends BST {
  constructor() {

//...super call
  }

//...
  static get _nil() {
    return _NULL_SENTINEL;
  }
}

In my Jest testfile:

const RBTree = require('../../../src/binary_trees/RBTree');
const RBNode = require('../../../src/binary_trees/RBNode');

When I step through the tests with with node-inspector:
1. At the bottom of RBTree.es6, RBTree._nil works correctly.
2. If I place a debugger after the lines in the testfile, RBTree._nil returns undefined.
3. RBTree._NULL_SENTINEL is the same object.

1 and 3 are working as expected.
Is the reason behind 2, that RBTree's static get function is running in a different scope and no longer has access to _NULL_SENTINEL? (due two separate exports?)

I'd want to attach something to the RBTree object such that the static get will work, but I'd prefer it not to be a pointer on this.

Solution

You are not importing the classes correctly. Since you are using a named export, you have to use a named import. As you can see through RBTree._NULL_SENTINEL, all the exports become properties of module. (why would _NULL_SENTINEL be a static property of the class RBTree? You are never assigning it to RBTree)

With ES6 it would be

import {RBTree} from '../../../src/binary_trees/RBTree';

and with CommonJS:

const RBTree = require('../../../src/binary_trees/RBTree').RBTree;