Add VERCEL_URl to env with URL parsing & transformation

src/env.mjs

@@ -15,6 +15,12 @@ const server = z.object({
  * To expose them to the client, prefix them with `NEXT_PUBLIC_`.
  */
 const client = z.object({
+    NEXT_PUBLIC_APP_URL: z.string().transform(url => {
+        // Add a HTTPS url prefix automatically, for vercel.
+        if (!(url.startsWith("http://") || url.startsWith("https://")))
+            return `https://${url}`;
+        return url;
+    })
     // NEXT_PUBLIC_CLIENTVAR: z.string().min(1),
 });
 
@@ -25,6 +31,7 @@ const client = z.object({
  */
 const processEnv = {
     NODE_ENV: process.env.NODE_ENV,
+    NEXT_PUBLIC_APP_URL: process.env.VERCEL_URL ?? process.env.APP_URL
     // NEXT_PUBLIC_CLIENTVAR: process.env.NEXT_PUBLIC_CLIENTVAR,
 };