npm run serve가 동작하지 않아요

3-7) 캐시 최적화를 듣고 있습니다.
npm run serve가 동작하지 않네요.

npm run build
npm run serve
의 순서로 실행했습니다.


에러 코드는 아래와 같습니다.
> lecture-3@0.1.0 serve

> node ./server/server.js

node:events:490

throw er; // Unhandled 'error' event

^

Error: listen EADDRINUSE: address already in use :::5000

at Server.setupListenHandle [as _listen2] (node:net:1774:16)

at listenInCluster (node:net:1822:12)

at Server.listen (node:net:1910:7)

at Function.listen (/Users/stellamax/Desktop/study/optimizing/node_modules/express/lib/application.js:618:24)

at Object.<anonymous> (/Users/stellamax/Desktop/study/optimizing/server/server.js:20:5)

at Module._compile (node:internal/modules/cjs/loader:1275:14)

at Module._extensions..js (node:internal/modules/cjs/loader:1329:10)

at Module.load (node:internal/modules/cjs/loader:1133:32)

at Module._load (node:internal/modules/cjs/loader:972:12)

at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:83:12)

Emitted 'error' event on Server instance at:

at emitErrorNT (node:net:1801:8)

at process.processTicksAndRejections (node:internal/process/task_queues:82:21) {

code: 'EADDRINUSE',

errno: -48,

syscall: 'listen',

address: '::',

port: 5000

}

클론 받은 코드는 아래와 같습니다.const express = require('express')
const app = express()
const port = 5000
const path = require('path')


const header = {
    setHeaders: (res, path) => {
        res.setHeader('Cache-Control', 'private, no-cache, no-store, must-revalidate')
        res.setHeader('Expires', '-1')
        res.setHeader('Pragma', 'no-cache')
    },
}

app.use(express.static(path.join(__dirname, '../build'), header))
app.get('*', (req, res) => {
    res.sendFile(path.join(__dirname, '../build/index.html'))
})

app.listen(port, () => console.log(`Example app listening at http://localhost:${port}`))