[color engine] Refactor rgb() and hsl() functions

src/color/__tests__/hsl.spec.ts

@@ -118,14 +118,7 @@ describe('hsl', () => {
     expect(hsl('transparent')).toEqual({ h: NaN, s: 0, l: 0, a: 0 })
   })
 
-  values = ['#FF33CC', 'rgb(255, 51, 204)', 'blue', 'transparent']
-  values.forEach(color => {
-    it(`does not recognize non-HSL string if \`only\` flag is true: ${color}`, () => {
-      expect(hsl(color, true)).toBeNull()
-    })
-  })
-
-  it('returns null if not a valid color string', () => {
-    expect(hsl('foo')).toBeNull()
+  it('throws if argument is not a valid color string', () => {
+    expect(() => hsl('foo')).toThrow()
   })
 })

src/color/__tests__/rgb.spec.ts

@@ -123,11 +123,7 @@ describe('rgb', () => {
     })
   })
 
-  it('does not recognize non-RGB string if `only` flag is true', () => {
-    expect(rgb('hsl(315, 100%, 60%)', true)).toBeNull()
-  })
-
-  it('returns null if not a valid color string', () => {
-    expect(rgb('foo')).toBeNull()
+  it('throws if argument is not a valid color string', () => {
+    expect(() => rgb('foo')).toThrow()
   })
 })

src/color/hsl.ts

@@ -1,7 +1,7 @@
 import { clamp } from '../utils'
 import angle, { normalizeAngle } from './angle'
 import { matchHslString } from './parsers/hslString'
-import rgb from './rgb'
+import rgb, { rgbFromColorString } from './rgb'
 import rgbToHsl from './transforms/rgbToHsl'
 
 /** Object model of a color in the HSL space */
@@ -44,10 +44,7 @@ export function normalizeHsl(hsl: HSL): HSL {
   }
 }
 
-function hslFromHslString(colorString: string): HSL | null {
-  const match = matchHslString(colorString)
-  if (!match) return null
-
+function hslFromParsedHslString(match: string[]): HSL {
   const hslValues = match.map(val => parseFloat(val))
 
   let alpha = hslValues[3] ?? 1
@@ -65,22 +62,38 @@ function hslFromHslString(colorString: string): HSL | null {
 }
 
 function hslFromRgbString(colorString: string): HSL | null {
-  const rgbColor = rgb(colorString, true)
+  const rgbColor = rgbFromColorString(colorString)
   return rgbColor ? rgbToHsl(rgbColor) : null
 }
 
 /**
- * Creates an HSL model from a given color string
+ * Creates an HSL model from a given HSL-based color string
  *
  * @param colorString - CSS color string
- * @param only - when `true`, does not convert non-RGB color
  * @returns an `{h,s,l,a}` color object (or `null` if invalid color string)
  */
-export default function hsl(colorString: string, only?: boolean): HSL | null {
+export function hslFromColorString(colorString: string): HSL | null {
   colorString = colorString.trim()
 
-  return (
-    hslFromHslString(colorString) ??
-    ((!only && hslFromRgbString(colorString)) || null)
-  )
+  let match: string[] | null
+  if ((match = matchHslString(colorString)) !== null)
+    return hslFromParsedHslString(match)
+
+  return null
+}
+
+/**
+ * Creates an HSL model from a given color string
+ *
+ * @param colorString - CSS color string
+ * @returns an `{h,s,l,a}` color object
+ * @throws if argument is not a valid color string
+ */
+export default function hsl(colorString: string): HSL {
+  const hslObj =
+    hslFromColorString(colorString) ?? hslFromRgbString(colorString)
+
+  if (hslObj === null) throw new Error('Invalid color string')
+
+  return hslObj
 }

src/color/rgb.ts

@@ -1,5 +1,5 @@
 import { clamp } from '../utils'
-import hsl from './hsl'
+import hsl, { hslFromColorString } from './hsl'
 import named from './named'
 import { matchHexString } from './parsers/hexString'
 import { matchRgbString } from './parsers/rgbString'
@@ -44,10 +44,7 @@ export function normalizeRgb(rgb: RGB): RGB {
   }
 }
 
-function rgbFromHexString(colorString: string): RGB | null {
-  const match = matchHexString(colorString)
-  if (!match) return null
-
+function rgbFromParsedHexString(match: string[]): RGB {
   const rgbValues = match.map(val => {
     // Expand if value is shorthand (single digit) hex
     if (val.length === 1) {
@@ -63,10 +60,7 @@ function rgbFromHexString(colorString: string): RGB | null {
   return { r: rgbValues[0], g: rgbValues[1], b: rgbValues[2], a: alpha }
 }
 
-function rgbFromRgbString(colorString: string): RGB | null {
-  const match = matchRgbString(colorString)
-  if (!match) return null
-
+function rgbFromParsedRgbString(match: string[]): RGB {
   const rgbValues = match.map((val, index) => {
     let num = parseFloat(val)
     if (val.indexOf('%') > -1) {
@@ -88,18 +82,17 @@ function rgbFromRgbString(colorString: string): RGB | null {
 }
 
 function rgbFromHslString(colorString: string): RGB | null {
-  const hslColor = hsl(colorString, true)
+  const hslColor = hslFromColorString(colorString)
   return hslColor ? hslToRgb(hslColor) : null
 }
 
 /**
- * Creates an RGB model from a given color string
+ * Creates an RGB model from a given RGB-based color string
  *
  * @param colorString - CSS color string
- * @param only - when `true`, does not convert non-RGB color
  * @returns an `{r,g,b,a}` color object (or `null` if invalid color string)
  */
-export default function rgb(colorString: string, only?: boolean): RGB | null {
+export function rgbFromColorString(colorString: string): RGB | null {
   colorString = colorString.trim()
 
   if (colorString.toLowerCase() === 'transparent')
@@ -111,9 +104,27 @@ export default function rgb(colorString: string, only?: boolean): RGB | null {
     colorString = hexFromName
   }
 
-  return (
-    rgbFromHexString(colorString) ??
-    rgbFromRgbString(colorString) ??
-    ((!only && rgbFromHslString(colorString)) || null)
-  )
+  let match: string[] | null
+  if ((match = matchHexString(colorString)) !== null)
+    return rgbFromParsedHexString(match)
+  else if ((match = matchRgbString(colorString)) !== null)
+    return rgbFromParsedRgbString(match)
+
+  return null
+}
+
+/**
+ * Creates an RGB model from a given color string
+ *
+ * @param colorString - CSS color string
+ * @returns an `{r,g,b,a}` color object (or `null` if invalid color string)
+ * @throws if argument is not a valid color string
+ */
+export default function rgb(colorString: string): RGB {
+  const rgbObj =
+    rgbFromColorString(colorString) ?? rgbFromHslString(colorString)
+
+  if (rgbObj === null) throw new Error('Invalid color string')
+
+  return rgbObj
 }