Whoo got unit tests that are failing...

src/hsl.ts

@@ -0,0 +1,40 @@
+import RGB from "./rgb"
+
+export default class HSL {
+    hue: number
+    saturation: number
+    lightness: number
+
+    constructor(hue: number, saturation: number, lightness: number) {
+        this.hue = (hue + 360) % 360
+        this.saturation = saturation
+        this.lightness = lightness
+    }
+
+    // https://en.wikipedia.org/wiki/RGB_color_model
+    public static fromRgb(rgb: RGB) {
+        const redValue = rgb.red / 255,
+            greenValue = rgb.green / 255,
+            blueValue = rgb.blue / 255,
+            lightness = (redValue + greenValue + blueValue) / 3,
+            saturation = 1 - (3 / (redValue + greenValue + blueValue)) * Math.min(redValue, greenValue, blueValue)
+
+        const dividend = (redValue - greenValue) + (redValue - blueValue)
+        const divisor = 2 * Math.sqrt((redValue - greenValue) ^ 2 + (redValue - blueValue) * (greenValue - blueValue))
+        let hue = (1 / Math.cos(dividend / divisor))
+        if (greenValue > blueValue) hue = 360 - hue
+
+        return new HSL(hue, saturation, lightness)
+    }
+
+    public static fromHex(color: number): HSL {
+        const red = color >> 16
+        const green = (color - (red << 16)) >> 8
+        const blue = color - (red << 16) - (green << 8)
+        return HSL.fromRgb(new RGB(red, green, blue))
+    }
+
+    public toHex(): number {
+        return RGB.fromHsl(this).toHex()
+    }
+}