allow transparent values

index.js

@@ -28,7 +28,7 @@ var rgb2hex = module.exports = function rgb2hex(color) {
     /**
      * parse input
      */
-    var digits = /(.*?)rgb(a)??\((\d{1,3}),(\d{1,3}),(\d{1,3})(,(1|0??\.([0-9]{0,3})))??\)/.exec(strippedColor);
+    var digits = /(.*?)rgb(a)??\((\d{1,3}),(\d{1,3}),(\d{1,3})(,([01]|0??\.([0-9]{0,3})))??\)/.exec(strippedColor);
 
     if(!digits) {
         // or throw error if input isn't a valid rgb(a) color

rgb2hex.js

@@ -21,7 +21,7 @@
         /**
          * parse input
          */
-        var digits = /(.*?)rgb(a)??\((\d{1,3}),(\d{1,3}),(\d{1,3})(,(1|0??\.([0-9]{0,3})))??\)/.exec(strippedColor);
+        var digits = /(.*?)rgb(a)??\((\d{1,3}),(\d{1,3}),(\d{1,3})(,([01]|0??\.([0-9]{0,3})))??\)/.exec(strippedColor);
 
         if(!digits) {
             // or throw error if input isn't a valid rgb(a) color

test/rgb2hex.test.js

@@ -5,39 +5,39 @@ const invalidErrorMessage = (input) => 'given color (' + input + ') isn\'t a val
 describe('rgb2hex should', () => {
     describe('throw an error if input is not typeof string', () => {
         it('[Object] {color: \'something\'}', () => {
-            var input = {color: 'something'}
+            const input = {color: 'something'}
             expect(() => rgb2hex(input)).toThrow(typeofErrorMessage)
         })
 
         it('[Function] function(){}', () => {
-            var input = function(){}
+            const input = function(){}
             expect(() => rgb2hex(input)).toThrow(typeofErrorMessage)
         })
 
         it('[Number] 231', () => {
-            var input = 231
+            const input = 231
             expect(() => rgb2hex(input)).toThrow(typeofErrorMessage)
         })
     })
 
     describe('throw an error if input is invalid', () => {
         it('notacolor', () => {
-            var input = 'notacolor'
+            const input = 'notacolor'
             expect(() => rgb2hex(input)).toThrow(invalidErrorMessage(input))
         })
 
         it('rgba(100, 100)', () => {
-            var input = 'rgb(100, 100)'
+            const input = 'rgb(100, 100)'
             expect(() => rgb2hex(input)).toThrow(invalidErrorMessage(input))
         })
 
         it('rgba(100, 10a0, 200, 300)', () => {
-            var input = 'rgba(100, 10a0, 200, 300)'
+            const input = 'rgba(100, 10a0, 200, 300)'
             expect(() => rgb2hex(input)).toThrow(invalidErrorMessage(input))
         })
 
         it('rgba(23, 54, 4, -.33)', () => {
-            var input = 'rgba(23, 54, 4, -.33)'
+            const input = 'rgba(23, 54, 4, -.33)'
             expect(() => rgb2hex(input)).toThrow(invalidErrorMessage(input))
         })
     })
@@ -80,12 +80,12 @@ describe('rgb2hex should', () => {
         })
 
         it('by limiting alpha value to 1', () => {
-            var input = 'rgba(236,68,44,1)'
+            const input = 'rgba(236,68,44,1)'
             expect(rgb2hex(input).alpha).not.toBeGreaterThan(1)
         })
 
         it('by not accepting to big values', () => {
-            var input = 'rgba(1123, 54, 4, 0.33)'
+            let input = 'rgba(1123, 54, 4, 0.33)'
             expect(() => rgb2hex(input)).toThrow(invalidErrorMessage(input))
             input = 'rgba(113, 1154, 4, 0.33)'
             expect(() => rgb2hex(input)).toThrow(invalidErrorMessage(input))
@@ -98,6 +98,12 @@ describe('rgb2hex should', () => {
             input = 'rgba(12,173,22,1.67)'
             expect(() => rgb2hex(input)).toThrow(invalidErrorMessage(input))
         })
+
+        it('transparent color', () => {
+            const input = 'rgba(0, 0, 0, 0)'
+            expect(rgb2hex(input).alpha).toBe(0)
+            expect(rgb2hex(input).hex).toBe('#000000')
+        })
     })
 
     describe('not care about', () => {