Fix plugins order (#1334)

Ref #1333

While refactoring broke plugin order.

lib/svgo/plugins.js

@@ -11,32 +11,31 @@
  * @return {Object} output data
  */
 module.exports = function(data, info, plugins) {
-  const perItemPlugins = [];
-  const perItemReversePlugins = [];
-  const fullPlugins = [];
   // Try to group sequential elements of plugins array
+  // to optimize ast traversing
+  const groups = [];
+  let prev;
   for (const plugin of plugins) {
-    switch(plugin.type) {
+    if (prev && plugin.type == prev[0].type) {
+      prev.push(plugin);
+    } else {
+      prev = [plugin];
+      groups.push(prev);
+    }
+  }
+  for (const group of groups) {
+    switch(group[0].type) {
       case 'perItem':
-        perItemPlugins.push(plugin);
+        data = perItem(data, info, group);
         break;
       case 'perItemReverse':
-        perItemReversePlugins.push(plugin);
+        data = perItem(data, info, group, true);
         break;
       case 'full':
-        fullPlugins.push(plugin);
+        data = full(data, info, group);
         break;
     }
   }
-  if (perItemPlugins.length !== 0) {
-    data = perItem(data, info, perItemPlugins);
-  }
-  if (perItemReversePlugins.length !== 0) {
-    data = perItem(data, info, perItemReversePlugins, true);
-  }
-  if (fullPlugins.length !== 0) {
-    data = full(data, info, fullPlugins);
-  }
   return data;
 };
 

test/svgo/_index.js

@@ -46,4 +46,9 @@ describe('svgo', () => {
       });
       expect(normalize(result.data)).to.equal(expected);
   });
+  it('should handle plugins order properly', async () => {
+    const [original, expected] = await parseFixture('plugins-order.svg');
+      const result = optimize(original, { input: 'file', path: 'input.svg' });
+      expect(normalize(result.data)).to.equal(expected);
+  });
 });