fix undefined pos

src/components/DictionaryView.vue

@@ -407,7 +407,9 @@ export default {
       })
     ]).then(function(_) {
       self.waiting_for_metadata = false
-      self.pos_selected = posOptions[posTags[self.$route.params.pos]]
+      if (self.$route.params.pos) {
+        self.pos_selected = posOptions[posTags[self.$route.params.pos]]
+      }
       if(self.$route.name == 'search') {
         self.lang = self.$route.params.lang
         navigate_to_query(self, self.$route.params.query)