Added unitless zero option

.csscomb.json

@@ -9,6 +9,7 @@
     "block-indent": true,
     "stick-brace": "\n",
     "strip-spaces": true,
+    "unitless-zero": true,
     "always-semicolon": true,
     "sort-order": [
         [

README.md

@@ -40,6 +40,7 @@ Example configuration:
     "block-indent": true,
     "stick-brace": true,
     "strip-spaces": true,
+    "unitless-zero": true,
     "always-semicolon": true
 }
 ```

lib/csscomb.js

@@ -18,6 +18,7 @@ var Comb = function() {
         'colon-space',
         'rule-indent',
         'block-indent',
+        'unitless-zero',
         'sort-order'
     ];
     this._config = {};

lib/options/unitless-zero.js

@@ -0,0 +1,34 @@
+module.exports = {
+
+    /**
+     * Sets handler value.
+     *
+     * @param {Boolean} value Option value
+     * @returns {Object}
+     */
+    setValue: function(value) {
+        if (value === true) {
+            this._value = value;
+            return this;
+        }
+    },
+
+    /**
+     * Processes tree node.
+     * @param {String} nodeType
+     * @param {node} node
+     */
+    process: function(nodeType, node) {
+        if (nodeType === 'value' || nodeType === 'braces') {
+            node.forEach(function(child, index) {
+                if (
+                    (child[0] === 'percentage' ||
+                    child[0] === 'dimension' && ['cm', 'em', 'ex', 'pt', 'px'].indexOf(child[2][1]) !== -1) &&
+                        child[1][1] === '0') {
+                    node[index] = child[1];
+                }
+            });
+        }
+    }
+
+};

test/integral.expect.css

@@ -1,5 +1,5 @@
 /* foobar */
-@media all and (min-width:0px)
+@media all and (min-width:0)
 {
     /* :before — бордер */
     .radio-button_theme_normal .radio-button__radio:before
@@ -50,7 +50,7 @@ div p em
     border-bottom: 1px solid red;
 }
 
-@media all and (min-width:0px)
+@media all and (min-width:0)
 {
     /* В нажатом состоянии смещается вниз на 1px вся кнопка, текст не смещается */
     .button_pressed_yes.button_shadow_yes

test/integral.origin.css

@@ -26,8 +26,8 @@
     /* _focused_yes */
     .radio-button_theme_normal .radio-button__radio_focused_yes:before
     {
-        -moz-box-shadow: 0 0 6px 2px rgba(255,204,0,.7), 0 1px 0 rgba(0,0,0,.07);
-        box-shadow: 0 0 6px 2px rgba(255,204,0,.7), 0 1px 0 rgba(0,0,0,.07);
+        -moz-box-shadow: 0 0 6px 2px rgba(255,204,0,.7), 0px 1px 0px rgba(0,0,0,.07);
+        box-shadow: 0 0 6px 2px rgba(255,204,0,.7), 0px 1px 0px rgba(0,0,0,.07);
     }
 
 }

test/unitless-zero.js

@@ -0,0 +1,45 @@
+var Comb = require('../lib/csscomb');
+var assert = require('assert');
+
+describe('options/unitless-zero', function() {
+    var comb;
+
+    beforeEach(function() {
+        comb = new Comb();
+    });
+
+    it('Should remove units in zero-valued dimensions', function() {
+        comb.configure({ 'unitless-zero': true });
+        assert.equal(
+            comb.processString(
+                'div { margin: 0em; padding: 0px }'
+            ),
+            'div { margin: 0; padding: 0 }'
+        );
+        assert.equal(
+            comb.processString(
+                'div { margin: 0% }'
+            ),
+            'div { margin: 0 }'
+        );
+    });
+
+    it('Should remove units in zero-valued media-query params', function() {
+        comb.configure({ 'unitless-zero': true });
+        assert.equal(
+            comb.processString('@media all and (min-width: 0px) { div { margin: 0em; padding: 0px } }'),
+            '@media all and (min-width: 0) { div { margin: 0; padding: 0 } }'
+        );
+    });
+
+    it('Should not remove units (degs) in rotate property', function() {
+        comb.configure({ 'unitless-zero': true });
+        assert.equal(
+            comb.processString(
+                'div { -webkit-transform: rotate(0deg); }'
+            ),
+            'div { -webkit-transform: rotate(0deg); }'
+        );
+    });
+
+});