Merge pull request 'role' (#56) from role into master

Reviewed-on: http://git.feashow.cn/clay/mosr-web/pulls/56

src/fvcomponents/fvTableColumn/index.vue

@@ -49,7 +49,7 @@ import { isVNode } from 'vue'
     if(column && column?.formatter) {
       return column.formatter(row, column, value, $index) || '--'
     }
-    return value ? value.toString() : '--'
+    return value !== null && value !== undefined ? value.toString() : '--'
   }
 </script>