fix: fix title inferrence regression (close #208)

Author: yyx990803

lib/app/dataMixin.js

@@ -47,7 +47,17 @@ export default {
       return targetLang || defaultLang || {}
     },
     $title () {
-      return this.$page.frontmatter.title || this.$localeConfig.title || this.$site.title || ''
+      const page = this.$page
+      const siteTitle = this.$localeConfig.title || this.$site.title || ''
+      const selfTitle = page.frontmatter.home ? null : (
+        page.frontmatter.title || // explicit title
+        page.title // inferred title
+      )
+      return siteTitle
+        ? selfTitle
+          ? (siteTitle + ' | ' + selfTitle)
+          : siteTitle
+        : selfTitle || 'VuePress'
     },
     $description () {
       return this.$page.frontmatter.description || this.$localeConfig.description || this.$site.description || ''

lib/app/util.js

@@ -14,15 +14,3 @@ export function findPageForPath (pages, path) {
     }
   }
 }
-
-export function getTitle (siteTitle, page) {
-  const selfTitle = page.frontmatter.home ? null : (
-    page.frontmatter.title || // explicit title
-    page.title // inferred title
-  )
-  return siteTitle
-    ? selfTitle
-      ? (siteTitle + ' | ' + selfTitle)
-      : siteTitle
-    : selfTitle || 'VuePress'
-}

lib/default-theme/Layout.vue

@@ -21,7 +21,7 @@ import Home from './Home.vue'
 import Navbar from './Navbar.vue'
 import Page from './Page.vue'
 import Sidebar from './Sidebar.vue'
-import { pathToComponentName, getTitle, getLang } from '@app/util'
+import { pathToComponentName } from '@app/util'
 import { resolveSidebarItems } from './util'
 
 export default {
@@ -76,7 +76,7 @@ export default {
 
   created () {
     if (this.$ssrContext) {
-      this.$ssrContext.title = getTitle(this.$title, this.$page)
+      this.$ssrContext.title = this.$title
       this.$ssrContext.lang = this.$lang
       this.$ssrContext.description = this.$page.description || this.$description
     }
@@ -87,7 +87,7 @@ export default {
     // update title / meta tags
     this.currentMetaTags = []
     const updateMeta = () => {
-      document.title = getTitle(this.$title, this.$page)
+      document.title = this.$title
       document.documentElement.lang = this.$lang
       const meta = [
         {