Preserve conditional processing attributes

plugins/removeEmptyAttrs.js

@@ -1,5 +1,7 @@
 'use strict';
 
+const { attrsGroups } = require('./_collections.js');
+
 exports.type = 'perItem';
 
 exports.active = true;
@@ -14,16 +16,16 @@ exports.description = 'removes empty attributes';
  *
  * @author Kir Belevich
  */
-exports.fn = function(item) {
-
+exports.fn = function (item) {
   if (item.elem) {
-
-        item.eachAttr(function(attr) {
-            if (attr.value === '') {
+    item.eachAttr(function (attr) {
+      if (
+        attr.value === '' &&
+        // empty conditional processing attributes prevents elements from rendering
+        attrsGroups.conditionalProcessing.includes(attr.name) === false
+      ) {
         item.removeAttr(attr.name);
       }
     });
-
   }
-
 };

test/plugins/removeEmptyAttrs.02.svg

@@ -0,0 +1,18 @@
+Empty conditional processing attributes should be preserved
+to hide elements
+
+===
+
+<svg xmlns="http://www.w3.org/2000/svg">
+    <g requiredFeatures=""/>
+    <g requiredExtensions=""/>
+    <g systemLanguage=""/>
+</svg>
+
+@@@
+
+<svg xmlns="http://www.w3.org/2000/svg">
+    <g requiredFeatures=""/>
+    <g requiredExtensions=""/>
+    <g systemLanguage=""/>
+</svg>

test/regression.js

@@ -107,15 +107,15 @@ const runTests = async ({ svgFiles }) => {
       name === 'styling-css-10-f' ||
       // rect is converted to path which matches wrong styles
       name === 'styling-css-08-f' ||
-      // other cases which require complex changes
+      // external image
       name === 'struct-image-02-b' ||
+      // complex selectors are messed becase of converting shapes to paths
       name === 'struct-use-10-f' ||
       name === 'struct-use-11-f' ||
       name === 'styling-css-01-b' ||
       name === 'styling-css-03-b' ||
       name === 'styling-css-04-f' ||
       // mismatched draft cases
-      name === 'struct-cond-overview-03-f' ||
       name === 'struct-use-07-b'
     ) {
       console.info(`${name} is skipped`);