If element data has keys of type object they are exported as [object Object] instead of something meaningful

[nicky1038]

This behavior is not documented :(

Complex data sholud be allowed to be exported. As XML or at least stringified JSON.

It should also be possible to import the result correctly.

It would be even better if user is allowed to pass a callback to transform data as one wishes.

[hasanbalci]

From the GraphML Primer:

With the help of the extension GraphML-Attributes one can specify additional information of simple type for the elements of the graph. Simple type means that the information is restricted to scalar values, e.g. numerical values and strings. If you want to add structured content to graph elements you should use the key/data extension mechanism of GraphML.

Currently, this extension only supports GraphML-Attributes which are scalar values. Support for the key/data extension mechanism mentioned in the quote can be considered in the future. We are open to pull requests.