[ERROR] npm start 에러 / Error: listen EADDRINUSE: address already in use :::4000

에러 종류 : npm start 에러/ 포트를 쓰고 있다고 할 때
에러 메세지 : Error: listen EADDRINUSE: address already in use :::4000
해결 방법 : $ lsof -i TCP:서버번호 한 후, kill -9 PID번호 후, npm start
참고 링크
참조 링크 : https://jootc.com/p/201912253249

The issue describes an npm start failure caused by port 4000 already being in use. No file or test is named; review the project's troubleshooting or setup documentation first, and consider the work complete when this error and the lsof/kill resolution are documented clearly.

Written by the indexing model from the issue text.