redirect existing root paths to the corresponding defaultLanguage path

gatsby-node.ts

@@ -356,14 +356,27 @@ export const onCreatePage: GatsbyNode<any, Context>["onCreatePage"] = async ({
   page,
   actions,
 }) => {
-  const { createPage, deletePage } = actions
+  const { createPage, deletePage, createRedirect } = actions
 
-  // create routes without the lang prefix e.g. `/{path}` as our i18n plugin
-  // only creates `/{lang}/{path}` routes. This is useful on dev env to avoid
-  // getting a 404 since we don't have server side redirects
-  if (IS_DEV && page.path.startsWith(`/${defaultLanguage}`)) {
+  const isDefaultLang = page.path.startsWith(`/${defaultLanguage}`)
+
+  if (isDefaultLang) {
     const path = page.path.slice(3)
-    createPage({ ...page, path })
+
+    createRedirect({
+      fromPath: path,
+      toPath: page.path,
+      isPermanent: true,
+      ignoreCase: true,
+      force: true,
+    })
+
+    // create routes without the lang prefix e.g. `/{path}` as our i18n plugin
+    // only creates `/{lang}/{path}` routes. This is useful on dev env to avoid
+    // getting a 404 since we don't have server side redirects
+    if (IS_DEV) {
+      createPage({ ...page, path })
+    }
   }
 
   const isTranslated = page.context.locale !== defaultLanguage