infer title

Author: yyx990803

Diff for: lib/app/Content.js

@@ -1,27 +1,17 @@
 export default {
   created () {
     if (this.$ssrContext) {
-      const title = getMetadata(this, 'title')
-      if (title) {
-        this.$ssrContext.title = title
-      }
-
-      const lang = getMetadata(this, 'lang')
-      if (lang) {
-        this.$ssrContext.lang = lang
-      }
+      this.$ssrContext.title = getMetadata(this, 'title') || 'VuePress'
+      this.$ssrContext.lang = getMetadata(this, 'lang') || 'en'
     }
   },
   mounted () {
-    const title = getMetadata(this, 'title')
-    if (title) {
-      document.title = title
-    }
-
-    const lang = getMetadata(this, 'lang')
-    if (lang) {
-      document.documentElement.lang = lang
+    const updateMeta = () => {
+      document.title = getMetadata(this, 'title') || 'VuePress'
+      document.documentElement.lang = getMetadata(this, 'lang') || 'en'
     }
+    this.$watch('$page', updateMeta)
+    updateMeta()
   },
   render (h) {
     const componentName = this.$page.path === '/'
@@ -35,5 +25,5 @@ export default {
 }
 
 function getMetadata (vm, key) {
-  return vm.$page.frontmatter[key] || vm.$page[key]
+  return vm.$page.frontmatter[key] || vm.$page[key] || vm.$site[key]
 }

Diff for: lib/build.js

@@ -47,9 +47,7 @@ module.exports = async function build (sourceDir) {
   await Promise.all(options.siteData.pages.map(async (page) => {
     const context = {
       url: page.path,
-      userHeadTags,
-      title: 'VuePress',
-      lang: 'en'
+      userHeadTags
     }
 
     let html

Diff for: lib/prepare.js

@@ -60,7 +60,14 @@ async function resolveOptions (sourceDir) {
     const data = {
       path: urlPath
     }
+
+    // extract yaml frontmatter
     const frontmatter = yaml.loadFront(content)
+    // infer title
+    const titleMatch = frontmatter.__content.match(/^#+\s+(.*)/)
+    if (titleMatch) {
+      data.title = titleMatch[1]
+    }
     delete frontmatter.__content
     if (Object.keys(frontmatter).length) {
       data.frontmatter = frontmatter