interpolateColorBetween.js

interpolate(startValue, destValue, progress, data) {
  const r = lerp(startValue.color[0], destValue.color[0], progress);
  const g = lerp(startValue.color[1], destValue.color[1], progress);
  const b = lerp(startValue.color[2], destValue.color[2], progress);
  const a = lerp(startValue.valpha, destValue.valpha, progress);

  const color = Color.rgb(r, g, b, a)[data.format === 'rgba' ? 'rgb' : data.format]();

  return typeof color === 'string' ? color : color.string();
}