function grayscale(color) {
    if (color === 'transparent') return color;
    return toColorString(_extends__default["default"]({}, parseToHsl(color), {
      saturation: 0
    }));
  }
Converts the color to a grayscale, by reducing its saturation to 0.

@example
// Styles as object usage
const styles = {
  background: grayscale('#CCCD64'),
  background: grayscale('rgba(204,205,100,0.7)'),
}

// styled-components usage
const div = styled.div`
  background: ${grayscale('#CCCD64')};
  background: ${grayscale('rgba(204,205,100,0.7)')};
`

// CSS in JS Output
element {
  background: "#999";
  background: "rgba(153,153,153,0.7)";
}