Fix: merge array if vmid is undefined

examples/vuex-async/App.vue

@@ -10,7 +10,7 @@
   export default {
     metaInfo: {
       meta: [
-        { vmid: 'charset', charset: 'utf-8' }
+        { charset: 'utf-8' }
       ]
     }
   }

examples/webpack.config.babel.js

@@ -25,9 +25,9 @@ export default {
 
   module: {
     loaders: [
-      { test: /\.js$/, exclude: /node_modules/, loader: 'babel' },
-      { test: /\.vue$/, loader: 'vue' },
-      { test: /\.json$/, loader: 'json' }
+      { test: /\.js$/, exclude: /node_modules/, loader: 'babel-loader' },
+      { test: /\.vue$/, loader: 'vue-loader' },
+      { test: /\.json$/, loader: 'json-loader' }
     ]
   },
 

src/shared/getMetaInfo.js

@@ -43,7 +43,7 @@ export default function _getMetaInfo (options = {}) {
           let shared = false
           for (let sourceIndex in source) {
             const sourceItem = source[sourceIndex]
-            if (targetItem[tagIDKeyName] === sourceItem[tagIDKeyName]) {
+            if (targetItem[tagIDKeyName] && targetItem[tagIDKeyName] === sourceItem[tagIDKeyName]) {
               shared = true
               break
             }