fix empty comment

+import {trim} from 'lodash';
 import {createNamespacedHelpers} from 'vuex';
 const {mapActions} = createNamespacedHelpers('comment');
 import YAS from 'utils/yas-constants';
@@ -61,6 +62,17 @@ export default {
       }
     },
     async comment(content) {
+      content = trim(content);
+
+      if (!content) {
+        this.$createToast({
+          txt: '请输入评论内容',
+          type: 'warn',
+          time: 1000
+        }).show();
+        return;
+      }
+
       if (this.posting) {
         return;
       }