Will C2 ever support JSON arrays (or does it already? I haven't found it) Also if JSON is supported, will I be able to send arrays over Websockets?
You can send an array over a WebSocket by using its AsJSON expression.
Oh ok, will this allow the C2 app to recieve JSON too?
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Here is the Manual entry, you can see "Load JSON" There.
https://www.scirra.com/manual/108/array
or in storage context:
https://www.scirra.com/manual/120/webstorage