encode method Null safety

Implementation

String encode() {
  var properties = <String, dynamic>{};
  if (anchor != null) {
    properties["anchor"] = anchor?.toString().split('.').last.toLowerCase();
  }
  if (color != null) {
    properties["color"] = color?.toRGBA();
  }
  if (colorTransition != null) {
    properties["colorTransition"] = colorTransition?.encode();
  }
  if (intensity != null) {
    properties["intensity"] = intensity;
  }
  if (intensityTransition != null) {
    properties["intensityTransition"] = intensityTransition?.encode();
  }
  if (position != null) {
    properties["position"] = position;
  }
  if (positionTransition != null) {
    properties["positionTransition"] = positionTransition?.encode();
  }

  return json.encode(properties);
}