NoSuchMethodError when the template in the core-list-dart does not contain an inner tag

[fedy2]

When I declare a core-list-dart with this template:

      <template>
        {{model.name}}
      </template>

I get this exception:

Exception: Uncaught Error: The null object does not have a setter 'hidden='.

NoSuchMethodError: method not found: 'hidden='
Receiver: null
Arguments: [false]
Stack Trace:
#0      Object.noSuchMethod (dart:core-patch/object_patch.dart:45)
#1      CoreList.updateItem (package:core_elements/core_list_dart.dart:258:18)
#2      CoreList.refresh (package:core_elements/core_list_dart.dart:317:24)
#3      CoreList.initializeItems (package:core_elements/core_list_dart.dart:245:17)
#4      CoreList.initializeData.<anonymous closure> (package:core_elements/core_list_dart.dart:227:56)
#5      _RootZone.runUnary (dart:async/zone.dart:1151)
#6      _Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:496)
#7      _Future._propagateToListeners (dart:async/future_impl.dart:579)
#8      _Future._completeWithValue (dart:async/future_impl.dart:339)
#9      _Future._asyncComplete.<anonymous closure> (dart:async/future_impl.dart:401)
#10     _asyncRunCallbackLoop (dart:async/schedule_microtask.dart:41)
#11     _asyncRunCallback (dart:async/schedule_microtask.dart:48)
#12     _handleMutation (dart:html:40489)

Instead I get no exception when wrapping the polymer expression with a div tag:

      <template>
        <div>{{model.name}}</div>
      </template>

[jakemac53]

I think this is working as intended. If you don't have a div or some other block level element then the core-list won't work (each item will just be displayed inline next to the other items). You are also responsible for setting the height on the individual items to properly match up with the height that the core-list-dart expects each item to be, otherwise the viewport won't be the right size and things like scrollTo won't work as expected.

This is all a bit unfortunate but it does allow for maximum customization. For instance we could automatically wrap each list item in a div and set the height to the core-list height property, but we wouldn't know what type of overflow is desired (hidden? scroll? ellipsis?).

[jakemac53]

That being said we should probably at least throw a meaningful error in this case.

[fedy2]

A meaningful exception would be nice. Also a note in the documentation would be useful.