Colorscale NaN values

[bonfire27]

Feature request:

You don`t have currently a way to set the color or the behavior of nan values in go.Heatmap (cells become transparent) and go.scatter (markers become black).

it would be nice to have a property to set like
marker_colornan="lightgray"

or

nancolor="black"

[alexcjohnson]

Yep, this would be a great feature. Has been discussed before though, eg plotly/plotly.js#975, so I'll close this one. Thanks!