Ember 3.28: TypeError: this.containerClassNames.join is not a function

[danielxdam]

In Ember 3.28 with ember-modal-dialog 4.0.0 we are getting an error when opening the dialog:

Uncaught (in promise) TypeError: this.containerClassNames.join is not a function basic-dialog.js:37

It looks like basic-dialog.js at line 43 is expecting this.containerClassNames to be an array or null but instead it is a string of the css class names passed in @containerClassNames.

We are extending the ModalDialog class but we haven't made any changes to the @containerClassNames in our subclass. That argument is just being passed on to the parent.

This may be related to or a duplicate of: #374 .

[lukemelia]

I believe this is fixed.