[Feature Request] relayoutData returns a proper object/dict for 'update_layout' roundtrip and convenience

[sdementen]

Is your feature request related to a problem? Please describe.

The relayoutData is very useful yet it comes in a format Dict[str]->Any that is not very convenient as keys may have dot and [] notations like in 'xaxis.range[0]' and cannot roundtrip with fig.update_layout (like in fig.update_layout(**relayoutData))

Describe the solution you'd like

I would like to get as relayoutData a proper dict/object.
So instead of receiving:
{'xaxis.range[0]': '2019-01-01', 'xaxis.range[1]': '2019-02-07 04:21:40.9199'}
I would like to get
{'xaxis': {'range': ['2019-01-01', '2019-02-07 04:21:40.9199']}}
or even better
{'xaxis': {'range': [datetime(2019,1,1), datetime(2019,2,7,4,21,40.9199)]}}
(datetime could also be a pandas.timestamp)

[chriddyp]

Thanks for opening @sdementen ! Our current spec for addressing this is with a new property for the entire figure minus the data. See plotly/dash-core-components#584

[chriddyp]

Thanks for opening @sdementen ! Our current spec for addressing this is with a new property for the entire figure minus the data. See plotly/dash-core-components#584

[sdementen]

Even better indeed, thanks!