fix: double slash comments inside Sass maps (shellscape#60)

* Fix parsing double slash comments inside Sass maps

* Upgrade natives module to 1.1.6 to fix Gulp crash on latest Node

Author: jsnajdr

lib/tokenize.js

@@ -152,7 +152,7 @@ module.exports = function tokenize (input, options) {
 
       case closeParen:
         parentCount--;
-        isURLArg = !isURLArg && parentCount === 1;
+        isURLArg = isURLArg && parentCount > 0;
         tokens.push([')', ')',
           line, pos  - offset,
           line, next - offset,

package-lock.json

@@ -107,6 +107,37 @@ describe('Parser → Comment', () => {
         { type: 'paren', value: ')' }
       ]
     },
+    {
+      it: 'should parse double slash comments after nested function inside url function',
+      test: 'url(var()//comment\n)',
+      loose: true,
+      expected: [
+        { type: 'func', value: 'url' },
+        { type: 'paren', value: '(' },
+        { type: 'func', value: 'var' },
+        { type: 'paren', value: '(' },
+        { type: 'paren', value: ')' },
+        { type: 'comment', value: 'comment' },
+        { type: 'paren', value: ')' }
+      ]
+    },
+    {
+      it: 'should parse double slash comments inside Sass maps',
+      test: '(a:(b:c)//comment\n)',
+      loose: true,
+      expected: [
+        { type: 'paren', value: '(' },
+        { type: 'word', value: 'a' },
+        { type: 'colon', value: ':' },
+        { type: 'paren', value: '(' },
+        { type: 'word', value: 'b' },
+        { type: 'colon', value: ':' },
+        { type: 'word', value: 'c' },
+        { type: 'paren', value: ')' },
+        { type: 'comment', value: 'comment' },
+        { type: 'paren', value: ')' }
+      ]
+    },
     {
       it: 'should parse only one double slash empty comment',
       test: '//\n',