Resolve id into a context-node.
function _contextGet(contextNodeOrId) {
        if (this._nodesById && ((contextNodeOrId instanceof String) || (typeof contextNodeOrId === 'string'))) {
            var renderNode = this._nodesById[contextNodeOrId];
            if (!renderNode) {
                return undefined;
            }

            // Return array
            if (renderNode instanceof Array) {
                var result = [];
                for (var i = 0, j = renderNode.length; i < j; i++) {
                    result.push({
                        renderNode: renderNode[i],
                        arrayElement: true
                    });
                }
                return result;
            }

            // Create context node
            return {
                renderNode: renderNode,
                byId: true
            };
        }
        else {
            return contextNodeOrId;
        }
    }