SASS - Convert HWB to RGB

gistfile1.sass

@function hslToRgb($hsl-color) {
    @return mix($hsl-color,$hsl-color);
}

@function hwbToRgb($hue, $white, $black, $alpha: 1) {
  
  // convert white and black values to decimals
  $white: if($white != 0, $white / 100%, $white);
  $black: if($black !=0, $black / 100%, $black);

  $rgb: hslToRgb(hsl($hue, 100%, 50%));
  $red: ( red($rgb) / 255 ) * (1 - $white - $black);
  $red: $red + $white;

  $green: ( green($rgb) / 255 ) * (1 - $white - $black);
  $green: $green + $white;

  $blue: ( blue($rgb) / 255 ) * (1 - $white - $black);
  $blue: $blue + $white;

  @return rgba($red * 255, $green * 255, $blue * 255, $alpha);
}

// hwb here is represented as degree, then white and black as a percentage
$test: hwbToRgb(60, 20%, 20%);

body{
  background: $test;
}