From bd7d82b5503de8eaff5783da7f52e6df734629fc Mon Sep 17 00:00:00 2001
From: Rachael Sewell <rachmari@github.com>
Date: Fri, 5 Nov 2021 09:43:47 -0700
Subject: [PATCH] fallback to English page when translation unavailable
 (#22638)

---
 middleware/find-page.js | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/middleware/find-page.js b/middleware/find-page.js
index f992672256..2830a7863a 100644
--- a/middleware/find-page.js
+++ b/middleware/find-page.js
@@ -3,11 +3,31 @@
 export default async function findPage(req, res, next) {
   let page = req.context.pages[req.pagePath]
 
-  // if this is a localized request that can't be found, try finding an English variant
+  // When a user navigates to a translated page that doesn't yet exists
+  // we want to first check if there is an English page with the same relative
+  // path.
+  // If an exact match in English doesn't exist, the requested page might have
+  // a redirect configured to a new page. This happens when an English page is
+  // renamed and Crowdin hasn't synced the new file.
+  // In both cases, redirect to the English page. If we don't redirect most
+  // components won't refresh and everything except the article will render
+  // in req.language.
   if (!page && req.language !== 'en') {
     const englishPath = req.pagePath.replace(new RegExp(`^/${req.language}`), '/en')
     // NOTE the fallback page will have page.languageCode = 'en'
     page = req.context.pages[englishPath]
+    const redirectToPath = req.context.redirects[englishPath]
+
+    // If the requested translated page has a 1-1 mapping in English,
+    // redirect to that English page
+    if (page) {
+      return res.redirect(301, englishPath)
+    }
+    // If the English file was renamed and has a redirect that matches the
+    // requested page's href, redirect to the new English href
+    if (redirectToPath) {
+      return res.redirect(301, redirectToPath)
+    }
   }
 
   if (page) {