Revert "fix: duplicate meta in ssr"

This reverts commit 5a02e2a.

Author: ludanxer

Diff for: packages/@vuepress/core/lib/client/index.ssr.html

@@ -7,6 +7,7 @@
     <meta name="description" content="{{ description }}">
     <meta name="generator" content="VuePress {{ version }}">
     {{{ userHeadTags }}}
+    {{{ pageMeta }}}
     {{{ renderResourceHints() }}}
     {{{ renderStyles() }}}
   </head>

Diff for: packages/@vuepress/core/lib/node/build/index.js

@@ -138,9 +138,14 @@ module.exports = class Build extends EventEmitter {
     readline.cursorTo(process.stdout, 0)
     process.stdout.write(`Rendering page: ${pagePath}`)
 
+    // #565 Avoid duplicate description meta at SSR.
+    const meta = (page.frontmatter && page.frontmatter.meta || []).filter(item => item.name !== 'description')
+    const pageMeta = renderPageMeta(meta)
+
     const context = {
       url: page.path,
       userHeadTags: this.userHeadTags,
+      pageMeta,
       title: 'VuePress',
       lang: 'en',
       description: '',
@@ -220,6 +225,24 @@ function renderAttrs (attrs = {}) {
   }
 }
 
+/**
+ * Render meta tags
+ *
+ * @param {Array} meta
+ * @returns {Array<string>}
+ */
+
+function renderPageMeta (meta) {
+  if (!meta) return ''
+  return meta.map(m => {
+    let res = `<meta`
+    Object.keys(m).forEach(key => {
+      res += ` ${key}="${escape(m[key])}"`
+    })
+    return res + `>`
+  }).join('')
+}
+
 /**
  * find and remove empty style chunk caused by
  * https://github.com/webpack-contrib/mini-css-extract-plugin/issues/85