init commit,

99_references/supabase-examples/auth/nextjs/app/auth/callback/route.ts

@@ -0,0 +1,27 @@
+import { type EmailOtpType } from "@supabase/supabase-js"
+import { type NextRequest, NextResponse } from "next/server"
+import { createClient } from "@/utils/supabase/server"
+import { redirect } from "next/navigation"
+
+export async function GET(request: NextRequest) {
+  const { searchParams } = new URL(request.url)
+  const token_hash = searchParams.get("token_hash")
+  const type = searchParams.get("type") as EmailOtpType | null
+  const next = searchParams.get("next") ?? "/"
+
+  if (token_hash && type) {
+    const supabase = createClient()
+
+    const { error } = await supabase.auth.verifyOtp({
+      type,
+      token_hash,
+    })
+    if (!error) {
+      // redirect user to specified redirect URL or root of app
+      redirect(next)
+    }
+  }
+
+  // redirect the user to an error page with some instructions
+  redirect("/error")
+}