Added title to the exam generate

src/pages/api/exam/[module]/index.ts

@@ -1,7 +1,7 @@
 // Next.js API route support: https://nextjs.org/docs/api-routes/introduction
 import type {NextApiRequest, NextApiResponse} from "next";
 import {app} from "@/firebase";
-import {getFirestore, setDoc, doc} from "firebase/firestore";
+import {getFirestore, setDoc, doc, runTransaction, collection, query, where, getDocs} from "firebase/firestore";
 import {withIronSessionApiRoute} from "iron-session/next";
 import {sessionOptions} from "@/lib/session";
 import {Exam, InstructorGender, Variant} from "@/interfaces/exam";
@@ -47,8 +47,25 @@ async function POST(req: NextApiRequest, res: NextApiResponse) {
 	}
 	const {module} = req.query as {module: string};
 
-	const exam = {...req.body, module: module};
-	await setDoc(doc(db, module, req.body.id), exam);
+	  
+	try {
+		const exam = {...req.body, module: module};
+		await runTransaction(db, async (transaction) => {
 
-	res.status(200).json(exam);
+			const docRef = doc(db, module, req.body.id);
+			const docSnap = await transaction.get(docRef);
+	  
+			if (docSnap.exists()) {
+						throw new Error('Name already exists');
+			}
+
+	  
+			const newDocRef = doc(db, module, req.body.id);
+			transaction.set(newDocRef, exam);
+		});
+		res.status(200).json(exam);
+	  } catch (error) {
+		console.error("Transaction failed: ", error);
+		res.status(500).json({ok: false, error: (error as any).message});
+	  }
 }