getRootElement() fails when rootElement is an element

[apellerano-pw]

The rootElement documentation states it can be an element or a selector string, but getRootElement() only works with selector strings.

https://emberjs.com/api/ember/3.3/classes/Application/properties/rootElement?anchor=rootElement

We were testing out shadow DOM stuff in chrome and using an initializer to create the shadow DOM and then point rootElement to an element inside the shadow DOM. Unfortunately tests don't work because get-root-element.js only works when rootElement is a string that can be passed to a querySelector.

https://github.com/emberjs/ember-test-helpers/blob/master/addon-test-support/%40ember/test-helpers/dom/get-root-element.js#L21

If it's useful I can build an Ember Twiddle showing the crash

[rwjblue]

Welp. Thats just silly. Good catch, mind taking a shot at fixing?

[apellerano-pw]

Yeah I'll see what I can do