[nodemon] app crashed - waiting for file changes before starting...

안녕하세요.
자꾸 앱크러쉬가 나는데 왜그런지 모르겠습니다ㅠ 선생님 코드 복붙했는데..
db는 연결됨이라고 뜹니다..

const express = require('express')
const app = express()

app.use(express.static(__dirname + '/public'))

const { MongoClient } = require('mongodb')

let db
const url = 'mongodb+srv://admin:@cluster0.mongodb.net/?retryWrites=true&w=majority&appName=Cluster0'
new MongoClient(url).connect().then((client)=>{
console.log('DB연결성공')
db = client.db('forum');

}).catch((err)=>{
console.log(err)
})

app.listen(8080, () => {
console.log('http://localhost:8080에서 실행중')
})

app.get('/', (요청,응답) => {
응답.sendFile(__dirname + '/index.html')
});

app.get('/list', async (요청, 응답) => {
let result = await db.collection('post').find().toArray()
응답.send(result[0].title)
})

terminal
\

http://localhost:8080에서 실행중
DB연결성공
/Users/grace/Documents/nodejs/server.js:31
    응답.send(result[0].title)
                      ^

TypeError: Cannot read properties of undefined (reading 'title')
    at /Users/grace/Documents/nodejs/server.js:31:23
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

Node.js v20.12.2
[nodemon] app crashed - waiting for file changes before starting...