JS – Create object from the object name in a var – ES6

This question was already asked and answered here.

Unfortunately it seems that this does not work with a ES6 classes.

Relevant Code of the classes involved:

class ORM {
  construct() {
    let className = 'Task';
    new this[className]; //throws: ORM.js:25 Uncaught TypeError: this[className] is not a constructor
    new window[className]; //throws: ORM.js:26 Uncaught TypeError: window[className] is not a constructor
    new this[className](1); //throws: ORM.js:27 Uncaught TypeError: this[className] is not a constructor
    new window[className](1); //throws: ORM.js:28 Uncaught TypeError: window[className] is not a constructor
  }
}
class Task extends ORM {
    constructor(id = null) {}
}

Is there any equivilant for ES6? Am I just missing something?

And no I would like to not use eval. Except if it is my last resort.