Refactor transaction API to improve ID handling and error responses

src/pages/api/transactions/[id]/index.ts

@@ -3,9 +3,18 @@ import { transactions, accounts } from "../../../../data/store";
 import type { Transaction } from "../../../../types";
 
 export const PUT: APIRoute = async ({ request, params }) => {
+  const { id } = params;
+
+  if (!id) {
+    return new Response(JSON.stringify({ error: "Transaction ID is required" }), {
+      status: 400,
+      headers: { "Content-Type": "application/json" },
+    });
+  }
+
   try {
     const updates = (await request.json()) as Partial<Transaction>;
-    const transactionIndex = transactions.findIndex((t) => t.id === params.id);
+    const transactionIndex = transactions.findIndex((t) => t.id === id);
 
     if (transactionIndex === -1) {
       return new Response(JSON.stringify({ error: "Transaction not found" }), {
@@ -31,7 +40,7 @@ export const PUT: APIRoute = async ({ request, params }) => {
     const updatedTransaction: Transaction = {
       ...oldTransaction,
       ...updates,
-      id: params.id, // Ensure ID doesn't change
+      id: id, // Ensure ID doesn't change
     };
 
     // Add new amount to account balance
@@ -53,7 +62,16 @@ export const PUT: APIRoute = async ({ request, params }) => {
 };
 
 export const DELETE: APIRoute = async ({ params }) => {
-  const transactionIndex = transactions.findIndex((t) => t.id === params.id);
+  const { id } = params;
+
+  if (!id) {
+    return new Response(JSON.stringify({ error: "Transaction ID is required" }), {
+      status: 400,
+      headers: { "Content-Type": "application/json" },
+    });
+  }
+
+  const transactionIndex = transactions.findIndex((t) => t.id === id);
 
   if (transactionIndex === -1) {
     return new Response(JSON.stringify({ error: "Transaction not found" }), {