Fix accessing of parent of disconnected node while listerning for new

components.

Also add test.

src/index.js

@@ -60,7 +60,7 @@ const Alpine = {
 
                         // Discard any changes happening within an existing component.
                         // They will take care of themselves.
-                        if (node.parentElement.closest('[x-data]')) return
+                        if (node.parentElement && node.parentElement.closest('[x-data]')) return
 
                         this.discoverUninitializedComponents((el) => {
                             this.initializeComponent(el)

test/mutations.spec.js

@@ -15,11 +15,11 @@ test('catch disconnected nodes that were used as targets for any mutations', asy
 
     Alpine.start()
 
-    runObservers[0]([
+    runObservers.forEach(cb => cb([
         {
             target: document.createElement('div'),
             type: 'childList',
             addedNodes: [ document.createElement('div') ],
         }
-    ])
+    ]))
 })