[FIX] warning

src/components/PageHeader/index.jsx

@@ -25,7 +25,7 @@ export default {
   },
   mixins: [pathMixin],
   render() {
-    const { prefix, course, routes = [], tabList = [], loading } = this;
+    const { prefix, routes = [], tabList = [], loading } = this;
     const { logo, title, action, content, extraContent } = this.$slots;
     const showTabs = tabList && tabList.length > 0;
     return (