_getMaps( referenceMap, nodeRef ) {

		let maps = referenceMap.get( nodeRef );

		if ( maps === undefined ) {

			maps = {
				renderMap: new WeakMap(),
				frameMap: new WeakMap()
			};

			referenceMap.set( nodeRef, maps );

		}

		return maps;

	}
Returns a dictionary for a given node and update map which
is used to correctly call node update methods per frame or render.

@private
@param {WeakMap<Node, Object>} referenceMap - The reference weak map.
@param {Node} nodeRef - The reference to the current node.
@return {Object<string,WeakMap>} The dictionary.