handle deprecated locales and locale aliases in middleware

Author: pettinarip

next.config.js

@@ -162,21 +162,21 @@ module.exports = (phase, { defaultConfig }) => {
       }
 
       return [
+        // All primary redirects
+        ...redirects.flatMap(([source, destination, permanent]) =>
+          createRedirect(source, destination, permanent)
+        ),
+
         // Custom locale aliases redirects
-        { source: "/no/:path*", destination: "/nb/:path*", permanent: true },
+        { source: "/no/:path*", destination: "/nb/:path*/", permanent: true },
 
         // Deprecated locale redirects
+        { source: "/ph", destination: "/", permanent: true },
+        { source: "/ph/:path*", destination: "/:path*/", permanent: true },
         { source: "/pcm", destination: "/", permanent: false },
-        { source: "/pcm/:path*", destination: "/:path*", permanent: false },
+        { source: "/pcm/:path*", destination: "/:path*/", permanent: false },
         { source: "/fil", destination: "/", permanent: false },
-        { source: "/fil/:path*", destination: "/:path*", permanent: false },
-        { source: "/ph", destination: "/", permanent: false },
-        { source: "/ph/:path*", destination: "/:path*", permanent: false },
-
-        // All primary redirects
-        ...redirects.flatMap(([source, destination, permanent]) =>
-          createRedirect(source, destination, permanent)
-        ),
+        { source: "/fil/:path*", destination: "/:path*/", permanent: false },
       ]
     },
   }

src/lib/utils/url.ts

@@ -61,6 +61,20 @@ export const normalizeSlug = (slug: string) => {
   return `/${slug.replace(/^\/+|\/+$/g, "")}`
 }
 
+/**
+ * Extracts the first path segment from a pathname.
+ * Useful for extracting locale prefixes from URLs.
+ *
+ * @example
+ * getFirstSegment("/en/about") // "en"
+ * getFirstSegment("/about")    // "about"
+ * getFirstSegment("/")         // ""
+ */
+export const getFirstSegment = (pathname: string): string => {
+  const secondSlash = pathname.indexOf("/", 1)
+  return secondSlash === -1 ? pathname.slice(1) : pathname.slice(1, secondSlash)
+}
+
 /**
  * Converts a string to a URL-friendly slug
  * @param text - The text to convert (e.g., "Governance/DAO", "Bridge Aave 1", "Hello world")