diff --git a/lib/default-theme/DropdownLink.vue b/lib/default-theme/DropdownLink.vue
index 5573f8d3ef..10d0609a46 100644
--- a/lib/default-theme/DropdownLink.vue
+++ b/lib/default-theme/DropdownLink.vue
@@ -27,13 +27,12 @@
 </template>
 
 <script>
-import { isExternal, ensureExt } from './util'
 import NavLink from './NavLink.vue'
 import DropdownTransition from './DropdownTransition.vue'
 
 export default {
   components: { NavLink, DropdownTransition },
-  data() {
+  data () {
     return {
       open: false
     }
@@ -44,7 +43,7 @@ export default {
     }
   },
   methods: {
-    toggle() {
+    toggle () {
       this.open = !this.open
     }
   }
diff --git a/lib/default-theme/Layout.vue b/lib/default-theme/Layout.vue
index 2415059bc6..f45e52e236 100644
--- a/lib/default-theme/Layout.vue
+++ b/lib/default-theme/Layout.vue
@@ -56,7 +56,6 @@ export default {
       )
     },
     shouldShowSidebar () {
-      const { themeConfig } = this.$site
       const { frontmatter } = this.$page
       return (
         !frontmatter.layout &&
@@ -73,13 +72,13 @@ export default {
         this.$localePath
       )
     },
-    pageClasses() {
+    pageClasses () {
       const userPageClass = this.$page.frontmatter.pageClass
       return [
         {
           'no-navbar': !this.shouldShowNavbar,
           'sidebar-open': this.isSidebarOpen,
-          'no-sidebar': !this.shouldShowSidebar,
+          'no-sidebar': !this.shouldShowSidebar
         },
         userPageClass
       ]
@@ -92,7 +91,6 @@ export default {
       this.$ssrContext.lang = this.$lang
       this.$ssrContext.description = this.$page.description || this.$description
     }
-
   },
 
   mounted () {
diff --git a/lib/default-theme/NavLink.vue b/lib/default-theme/NavLink.vue
index 6cb61c8b4e..63104cce26 100644
--- a/lib/default-theme/NavLink.vue
+++ b/lib/default-theme/NavLink.vue
@@ -24,7 +24,7 @@ export default {
     }
   },
   computed: {
-    link() {
+    link () {
       return ensureExt(this.item.link)
     }
   },
diff --git a/lib/default-theme/NavLinks.vue b/lib/default-theme/NavLinks.vue
index 3f8b1c08e2..5b19cb9d60 100644
--- a/lib/default-theme/NavLinks.vue
+++ b/lib/default-theme/NavLinks.vue
@@ -35,7 +35,7 @@ export default {
     nav () {
       const { locales } = this.$site
       if (locales && Object.keys(locales).length > 1) {
-        let currentLink = this.$page.path
+        const currentLink = this.$page.path
         const routes = this.$router.options.routes
         const themeLocales = this.$site.themeConfig.locales || {}
         const languageDropdown = {
@@ -63,11 +63,11 @@ export default {
       return this.userNav
     },
     userLinks () {
-      return (this.nav || []).map((link => {
+      return (this.nav || []).map(link => {
         return Object.assign(resolveNavLinkItem(link), {
           items: (link.items || []).map(resolveNavLinkItem)
         })
-      }))
+      })
     },
     repoLink () {
       const { repo } = this.$site.themeConfig
@@ -93,7 +93,7 @@ export default {
       }
 
       return 'Source'
-    },
+    }
   }
 }
 </script>
diff --git a/lib/default-theme/Sidebar.vue b/lib/default-theme/Sidebar.vue
index 0bd13c83d3..ab3a4c5131 100644
--- a/lib/default-theme/Sidebar.vue
+++ b/lib/default-theme/Sidebar.vue
@@ -19,9 +19,9 @@
 
 <script>
 import SidebarGroup from './SidebarGroup.vue'
-import SidebarLink, { groupHeaders } from './SidebarLink.vue'
+import SidebarLink from './SidebarLink.vue'
 import NavLinks from './NavLinks.vue'
-import { isActive, resolveSidebarItems } from './util'
+import { isActive } from './util'
 
 export default {
   components: { SidebarGroup, SidebarLink, NavLinks },
diff --git a/lib/default-theme/SidebarLink.vue b/lib/default-theme/SidebarLink.vue
index b90329f00b..894aeaff41 100644
--- a/lib/default-theme/SidebarLink.vue
+++ b/lib/default-theme/SidebarLink.vue
@@ -34,7 +34,7 @@ function renderLink (h, to, text, active) {
     props: {
       to,
       activeClass: '',
-      exactActiveClass: '',
+      exactActiveClass: ''
     },
     class: {
       active,