the node id of the variable to query
const session = ...; // ClientSession
const nodeId = opcua.VariableIds.Server_ServerStatus_CurrentTime;
session.getBuiltInDataType(nodeId,function(err,dataType) {
assert(dataType === opcua.DataType.DateTime);
});
// or
nodeId = opcua.coerceNodeId("ns=2;s=Static_Scalar_ImagePNG");
const dataType: await session.getBuiltInDataType(nodeId);
assert(dataType === opcua.DataType.ByteString);
retrieve the built-in DataType of a Variable, from its DataType attribute.
this method is useful to determine which DataType to use when constructing a Variant