A weird construct in a class static method that makes the method inheritable by class extensions

index.js

'use strict'

class Foo {
  static createFoo() {
    return new Foo()
  }
}

class Bar {
  static createBar() {
    return new (this)()
  }
}

class Baz extends Foo {}

class FooBar extends Bar {}

const foo = Foo.createFoo()
console.log(foo instanceof Foo)

const bar = Bar.createBar()
console.log(bar instanceof Bar)

const baz1 = new Baz()
console.log(baz1 instanceof Baz)
console.log(baz1 instanceof Foo)

const baz2 = Baz.createFoo()
console.log(baz2 instanceof Baz)
console.log(baz2 instanceof Foo)

const foobar = FooBar.createBar()
console.log(foobar instanceof FooBar)
console.log(foobar instanceof Bar)