Show error on duplicate user registration

Author: tzyian

peerprep/app/actions/server_actions.ts

@@ -36,7 +36,13 @@ export async function signup(state: FormState, formData: FormData) {
     redirect("/auth/login");
   } else {
     // TODO: handle failure codes: 400, 409, 500.
-    console.log(`${json.status}: ${json.error}`);
+    console.log(`Error in signup: ${json.status}: ${json.error}`);
+    return {
+      errors: {
+        username: ["Username is already in use."],
+        email: ["Email is already in use."],
+      },
+    };
   }
 }
 

peerprep/app/auth/register/page.tsx

@@ -20,7 +20,11 @@ function RegisterPage() {
         )}
         <FormTextInput required label="Email:" name="email" />
         {state?.errors?.email && (
-          <p className={style.error}>{state.errors.email}</p>
+          <p className={style.error}>
+            {state.errors.email.map((item) => (
+              <div key={item}>{item}</div>
+            ))}
+          </p>
         )}
         <FormTextInput
           required