color method Null safety

dynamic color(
  1. String color,
  2. dynamic d

Set color converter function. This option should a function and the specified function receives color (e.g. '#ff0000') and d that has data parameters like id, value, index, etc. And it must return a string that represents color (e.g. '#00ff00').


external dynamic /*String|d3.Rgb*/ color(String color, dynamic d);