fix(theme-docs): remove redundant header (#722)

docs/content/en/themes/docs.md

@@ -329,7 +329,8 @@ To make it work properly, make sure to include these properties in the front-mat
 #### Optional fields
 
 - `category` (`String`)
-  - This will be used to group the documents in the navigation
+  - This will be used to group the documents in the navigation (defaults to `""`)
+  - If `category` is falsy or not a string, it is coerced to be an empty string, and isn't renderd in the sidebar.
 - `version` (`Float`)
   - Alert users that the page is new with a badge. Once the page is seen, the version is stored in the local storage until you increment it
 - `fullscreen` (`Boolean`)

packages/theme-docs/src/components/app/AppNav.vue

@@ -18,6 +18,7 @@
           }"
         >
           <p
+            v-if="category"
             class="mb-2 text-gray-500 uppercase tracking-wider font-bold text-sm lg:text-xs"
           >{{ category }}</p>
           <ul>

packages/theme-docs/src/index.js

@@ -41,10 +41,13 @@ function themeModule () {
   // Configure content after each hook
   hook('content:file:beforeInsert', (document) => {
     const regexp = new RegExp(`^/(${options.i18n.locales.map(locale => locale.code).join('|')})`, 'gi')
-    const dir = document.dir.replace(regexp, '')
-    const slug = document.slug.replace(/^index/, '')
+    const { dir, slug, category } = document
+    const _dir = dir.replace(regexp, '')
+    const _slug = slug.replace(/^index/, '')
+    const _category = category && typeof category === 'string' ? category : ''
 
-    document.to = `${dir}/${slug}`
+    document.to = `${_dir}/${_slug}`
+    document.category = _category
   })
   // Extend `/` route
   hook('build:extendRoutes', (routes) => {