Simplified callbacks into a single class with a detach function option so we can use them generically. Patached arrays can have multiple on push/on pop callbacks and moved over to this new model. Needs more testing and cleanup.

src/ignite-template.js

@@ -600,13 +600,15 @@ class list extends IgniteTemplate {
     }
 
     onListChanged(oldValue, newValue) {
+        console.log("On List changed:", newValue);
+
         this.list = newValue;
 
         IgniteRenderingContext.enter();
 
         try {
             this.construct(null); //The list changed, reconstruct this template.
-        } catch { }
+        } catch (error) { console.error(error); }
 
         IgniteRenderingContext.leave();
     }
@@ -616,7 +618,12 @@ class list extends IgniteTemplate {
 
         try {
             var template = this.forEach(this.list[this.list.length - 1]);
-            template.construct(this.element.parentElement, this.elements[this.elements.length - 1].nextSibling);
+
+            if (this.elements.length > 0) {
+                template.construct(this.element.parentElement, this.elements[this.elements.length - 1].nextSibling);
+            } else {
+                template.construct(this.element.parentElement, null);
+            }
 
             this.children.push(template);
             this.elements.push(template.element);