From 42b82de8ea53b0bbd5bf848a21df58e5146d0e8e Mon Sep 17 00:00:00 2001
From: Andreas Weber <weber.andreas@gmail.com>
Date: Sun, 19 Mar 2017 13:21:30 +0100
Subject: [PATCH] refactor attribute handling and add special handling for
 draggable

---
 lib/helpers.js        | 109 +++++++++++++++++++++++++++++++-----------
 lib/list.js           |   3 +-
 test/minimize-test.js |  25 +++++++++-
 3 files changed, 107 insertions(+), 30 deletions(-)

diff --git a/lib/helpers.js b/lib/helpers.js
index 7ad09bb..4b61295 100644
--- a/lib/helpers.js
+++ b/lib/helpers.js
@@ -108,7 +108,77 @@ Helpers.prototype.tag = function tag(element) {
 
   return '<' + element.name + this.attributes(element) + '>';
 };
-
+/** Is the attribute allowed on the HTML element? If so, allow special
+ * treatment. If not, then just return the full attribute and its value.
+ * @param {String} name name of the element
+ * @param {String} key name of the attribute
+ * @return {Boolean}
+ */
+Helpers.prototype.allowAttributeInNode = function (name, key) {
+  var attrDefinition = Object.hasOwnProperty.call(list.attributes, key) && list.attributes[key];
+  if (attrDefinition) {
+    return attrDefinition === '*' || ~attrDefinition.indexOf(name);
+  }
+  return ~key.indexOf('data-');
+}
+/** allow remove of attribute
+ * @param {String} name name of the element
+ * @param {String} key name of the attribute
+ * @param {String} value value of the attribute
+ * @return {Boolean}
+ */
+Helpers.prototype.allowRemoveAttributeValue = function (key, value) {
+  if (this.config.spare) {
+    return false;
+  }
+  if (!value) {
+    return true;
+  }
+  if (key === 'draggable') {
+    return value === 'auto';
+  }
+  return (value === 'true' || value === key) && ~list.redundant.indexOf(key);
+};
+/** allow remove of attribute value
+ * @param {String} name name of the element
+ * @param {String} key name of the attribute
+ * @param {String} value value of the attribute
+ * @return {Boolean}
+ */
+Helpers.prototype.allowRemoveAttribute = function (name, key, value) {
+  if (this.config.empty){
+    return false;
+  }
+  if (/data|itemscope/.test(key)) {
+    return false;
+  }
+  if (key === 'draggable') {
+    if (value === 'true') {
+      return ~['img','a'].indexOf(name)
+    } else if (value === 'false') {
+      return !~['img','a'].indexOf(name)
+    }
+  }
+  if (value) {
+    return false;
+  }
+  return !~list.redundant.indexOf(key);
+};
+/** create attribute string
+ * @param {String} key name of the attribute
+ * @param {String} value value of the attribute
+ * @return {String}
+ */
+Helpers.prototype.toAttributeString = function (key, value) {
+  var result = '';
+  if (key) {
+    result += ' ' + key;
+    if (value !== null) {
+      result += '=' + this.quote(!this.config.whitespace ? compact(value).trim() : value);
+    }
+  }
+  return result;
+};
 /**
  * Loop set of attributes belonging to an element. Surrounds attributes with
  * quotes if required, omits if not.
@@ -121,41 +191,26 @@ Helpers.prototype.attributes = function attributes(element) {
   var attr = element.attribs
     , self = this
     , name = element.name
-    , value, bool, allowed;
+    , value;
 
   if (!attr || typeof attr !== 'object') return '';
   return Object.keys(attr).reduce(function (result, key) {
     value = attr[key];
-    bool = ~list.redundant.indexOf(key);
-
-    //
-    // Is the attribute allowed on the HTML element? If so, allow special
-    // treatment. If not, then just return the full attribute and its value.
-    //
-    allowed = Object.hasOwnProperty.call(list.attributes, key) && list.attributes[key];
-    allowed = allowed
-      ? allowed === '*' || ~allowed.indexOf(name)
-      : ~key.indexOf('data-');
-
-    //
-    // Remove attributes that are empty, not boolean and no semantic value.
-    //
-    if (!self.config.empty && !/data|itemscope/.test(key) && !bool && !value && allowed) return result;
 
-    //
-    // Boolean attributes should be added sparse, also unset attributes
-    // should remain unset if retained with `empty` option.
-    //
-    result = result + ' ' + key;
-    if (!self.config.spare) {
-      if (!value.length) return result;
-      if (allowed && bool && (value === key || 'true' === value)) return result;
+    if (self.allowAttributeInNode(name, key)) {
+      if (self.allowRemoveAttribute(name, key, value)) {
+        key = null;
+        value = null;
+      }else if (self.allowRemoveAttributeValue(key, value)) {
+        value = null;
+      }
+    } else if (!value) {
+      value = null;
     }
-
     //
     // Return full attribute with value.
     //
-    return result + '=' + self.quote(!self.config.whitespace ? compact(value).trim() : value);
+    return result + self.toAttributeString(key, value);
   }, '');
 };
 
diff --git a/lib/list.js b/lib/list.js
index 1eec666..91b0624 100644
--- a/lib/list.js
+++ b/lib/list.js
@@ -25,7 +25,7 @@ exports.redundant = [
   'async', 'defer', 'formnovalidate', 'checked', 'scoped', 'reversed',
   'selected', 'autoplay', 'controls', 'loop', 'muted', 'seamless',
   'default', 'ismap', 'novalidate', 'open', 'typemustmatch', 'truespeed',
-  'itemscope', 'autocomplete', 'download', 'draggable', 'novalidate',
+  'itemscope', 'autocomplete', 'download', 'novalidate',
   'sortable', 'spellcheck'
 ];
 
@@ -137,7 +137,6 @@ exports.attributes = {
   'dirname': ['input', 'textarea'],
   'disabled': ['button', 'command', 'fieldset', 'input', 'keygen', 'optgroup', 'option', 'select', 'textarea'],
   'download': ['a', 'area'],
-  'draggable': '*',
   'dropzone': '*',
   'enctype': 'form',
   'for': ['label', 'output'],
diff --git a/test/minimize-test.js b/test/minimize-test.js
index 13bee6a..6cef314 100644
--- a/test/minimize-test.js
+++ b/test/minimize-test.js
@@ -306,7 +306,30 @@ describe('Minimize', function () {
         done();
       });
     });
-
+  it('should remove value from draggable attribute', function (done) {
+      minimize.parse('<div draggable="auto">', function (error, result) {
+        expect(result).to.equal('<div draggable></div>');
+        done();
+      });
+    });
+    it('should not remove value from draggable attribute', function (done) {
+      minimize.parse('<div draggable="true"></div>', function (error, result) {
+        expect(result).to.equal('<div draggable=true></div>');
+        done();
+      });
+    });
+    it('should remove draggable attribute from element', function (done) {
+      minimize.parse('<img draggable="true"/>', function (error, result) {
+        expect(result).to.equal('<img>');
+        done();
+      });
+    });
+    it('should remove draggable attribute from element', function (done) {
+      minimize.parse('<div draggable="false"></div>', function (error, result) {
+        expect(result).to.equal('<div></div>');
+        done();
+      });
+    });
     it('should remove CDATA from scripts', function (done) {
       minimize.parse(html.cdata, function (error, result) {
         expect(result).to.equal("<script type=text/javascript>\n\n...code...\n\n</script>");