npm i 하면 npm ERR! code ERESOLVE

서버파일에서 node 모듈 설치위한
npm i 하면 밑과 같은 에러출력

npm ERR! code ERESOLVE
npm ERR! ERESOLVE could not resolve
npm ERR! 
npm ERR! While resolving: @mochajs/json-file-reporter@1.3.0
npm ERR! Found: mocha@10.0.0
npm ERR! node_modules/mocha
npm ERR!   dev mocha@"^10.0.0" from the root project
npm ERR!   peer mocha@">=3.1.2" from mocha-multi-reporters@1.5.1
npm ERR!   node_modules/mocha-multi-reporters
npm ERR!     dev mocha-multi-reporters@"^1.5.1" from the root project
npm ERR! 
npm ERR! Could not resolve dependency:
npm ERR! peer mocha@"6.x || 7.x || 8.x" from @mochajs/json-file-reporter@1.3.0
npm ERR! node_modules/@mochajs/json-file-reporter
npm ERR!   dev @mochajs/json-file-reporter@"^1.3.0" from the root project
npm ERR! 
npm ERR! Conflicting peer dependency: mocha@8.4.0
npm ERR! node_modules/mocha
npm ERR!   peer mocha@"6.x || 7.x || 8.x" from @mochajs/json-file-reporter@1.3.0
npm ERR!   node_modules/@mochajs/json-file-reporter
npm ERR!     dev @mochajs/json-file-reporter@"^1.3.0" from the root project
npm ERR! 
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force, or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.
npm ERR! 
npm ERR! See /Users/mun/.npm/eresolve-report.txt for a full report.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/mun/.npm/_logs/2022-07-14T03_57_00_674Z-debug-0.log

원인

리액트 프로젝트 세팅시 항상 최신버전 설치되므로, 다른 라이브러리와 호환안됨
리액트 버전 변경해야할 때가 있음

해결

1. package.json 에서 라이브러리 버전을 호환되는 버전으로 맞추거나

2. --save --legacy-peer-deps 뒤에 입력하기
   : 기존버전 무시하고 설치한다는 뜻

npm install --save --legacy-peer-deps

3. 아니면 npm install --force

참고

https://stackoverflow.com/questions/64573177/unable-to-resolve-dependency-tree-error-when-installing-npm-packages

https://curryyou.tistory.com/479