making sure that source colors won't be converted into chroma.colors

package.json

@@ -1,7 +1,7 @@
 {
     "name"         : "chroma-js",
     "description"  : "JavaScript library for color conversions",
-    "version"      : "0.4.13",
+    "version"      : "0.4.14",
     "author"       : "Gregor Aisch",
     "homepage"     : "https://github.com/gka/chroma.js",
     "keywords"     : ["color"],

src/colorscale.coffee

@@ -55,7 +55,9 @@ class ColorScale
         if not colors?
             colors = ['#ddd', '#222']
         if colors? and type(colors) == 'string' and chroma.brewer?[colors]?
-            colors = chroma.brewer[colors].slice(0)
+            colors = chroma.brewer[colors]
+        # make a copy of the colors
+        colors = colors.slice(0)
         # convert to chroma classes
         for c in [0..colors.length-1]
             col = colors[c]

test/scales-test.coffee

@@ -66,6 +66,18 @@ vows
 
                 #assert.deepEqual res, [0.33, 0.33, 0.33, 0.33, 0.80, 100]
 
+        'source array keeps untouched':
+            topic: chroma.brewer.Blues.slice(0)
+            'colors are an array': (colors) ->
+                assert.equal colors.length, 9
+            'colors are strings': (colors) ->
+                assert.equal typeof colors[0], 'string'
+            'creating a color scale': (colors) ->
+                chroma.scale(colors)
+                assert true
+            'colors are still strings': (colors) ->
+                assert.equal typeof colors[0], 'string'
+
         # 'fixed color scale':
         #     topic: ->
         #         cs = new chroma.ColorScale()