joomla-tab createNavs and removeNavs will never Execute

[Weiskopfseeadler]

the function createNavs and removeNavs can not execute becaus of the fihrst if

if ((tab instanceof Element && tab.tagName.toLowerCase() !== 'joomla-tab-element') || ![].some.call(this.children, (el) => el === tab).length || !tab.getAttribute('name') || !tab.getAttribute('id')) return;
The problem is with
![].some.call(this.children, (el) => el === tab).length
some returns true or fals and does not have length. Therfor it is always true.
Remove lenth and it will work