mergeTo TypeError: Cannot read property 'isPlaying' of null

Description:

• A-Frame Version: 0.7.0
• Platform / Device: chrome
• Reproducible Code Snippet or URL:

hello i tried to merge two objects with this simple code

<a-entity id="target" geometry="primitive: box; buffer: false; skipCache: true" material="color: red"></a-entity>
<a-entity geometry="primitive: box; buffer: false; skipCache: true; mergeTo: #target"
          material="color: red" position="1 2 3"></a-entity>

and i receive this error

ERROR Error: Uncaught (in promise): TypeError: Cannot read property ‘isPlaying’ of null TypeError: Cannot read property ‘isPlaying’ of null

how is possible? i just tried the example of this page

https://github.com/aframevr/aframe/blob/master/docs/components/geometry.md

[ngokevin]

I think we should remove the mergeTo property, it works better if done manually versus declaratively (and it seems stale). I’d recommend merging manually in an A-Frame component what you need.

[ngokevin]

I made a geometry merge component: https://github.com/ngokevin/kframe/tree/master/components/geometry-merger#aframe-geometry-merger-component