React acting weird (compiled with problems 9 errors) - reactjs

Question

I've been working with react using mern stack. Everything was fine until I used JSON.parse in a function when getting data out of the mongo database. I clicked save and I got 9 errors. I removed all the code, everything relating to it as if I never attempted it and I'm still getting these 9 errors shown below:
Any pointers?
Compiled with problems:X
ERROR in ./node_modules/cookie-signature/index.js 4:13-30
Module not found: Error: Can't resolve 'crypto' in '/Users/sebastianrichards/ReactProject/client/node_modules/cookie-signature'
BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.
This is no longer the case. Verify if you need this module and configure a polyfill for it.
If you want to include a polyfill, you need to:
- add a fallback 'resolve.fallback: { "crypto": require.resolve("crypto-browserify") }'
- install 'crypto-browserify'
If you don't want to include a polyfill, you can use an empty module like this:
resolve.fallback: { "crypto": false }
ERROR in ./node_modules/destroy/index.js 15:17-41
Module not found: Error: Can't resolve 'fs' in '/Users/sebastianrichards/ReactProject/client/node_modules/destroy'
ERROR in ./node_modules/destroy/index.js 19:11-26
Module not found: Error: Can't resolve 'zlib' in '/Users/sebastianrichards/ReactProject/client/node_modules/destroy'
BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.
This is no longer the case. Verify if you need this module and configure a polyfill for it.
If you want to include a polyfill, you need to:
- add a fallback 'resolve.fallback: { "zlib": require.resolve("browserify-zlib") }'
- install 'browserify-zlib'
If you don't want to include a polyfill, you can use an empty module like this:
resolve.fallback: { "zlib": false }
ERROR in ./node_modules/etag/index.js 18:13-30
Module not found: Error: Can't resolve 'crypto' in '/Users/sebastianrichards/ReactProject/client/node_modules/etag'
BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.
This is no longer the case. Verify if you need this module and configure a polyfill for it.
If you want to include a polyfill, you need to:
- add a fallback 'resolve.fallback: { "crypto": require.resolve("crypto-browserify") }'
- install 'crypto-browserify'
If you don't want to include a polyfill, you can use an empty module like this:
resolve.fallback: { "crypto": false }
ERROR in ./node_modules/etag/index.js 20:12-31
Module not found: Error: Can't resolve 'fs' in '/Users/sebastianrichards/ReactProject/client/node_modules/etag'
ERROR in ./node_modules/express/lib/response.js 25:11-26
Module not found: Error: Can't resolve 'http' in '/Users/sebastianrichards/ReactProject/client/node_modules/express/lib'
BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.
This is no longer the case. Verify if you need this module and configure a polyfill for it.
If you want to include a polyfill, you need to:
- add a fallback 'resolve.fallback: { "http": require.resolve("stream-http") }'
- install 'stream-http'
If you don't want to include a polyfill, you can use an empty module like this:
resolve.fallback: { "http": false }
ERROR in ./node_modules/express/lib/utils.js 31:18-40
Module not found: Error: Can't resolve 'querystring' in '/Users/sebastianrichards/ReactProject/client/node_modules/express/lib'
BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.
This is no longer the case. Verify if you need this module and configure a polyfill for it.
If you want to include a polyfill, you need to:
- add a fallback 'resolve.fallback: { "querystring": require.resolve("querystring-es3") }'
- install 'querystring-es3'
If you don't want to include a polyfill, you can use an empty module like this:
resolve.fallback: { "querystring": false }
ERROR in ./node_modules/mime/mime.js 3:9-22
Module not found: Error: Can't resolve 'fs' in '/Users/sebastianrichards/ReactProject/client/node_modules/mime'
ERROR in ./node_modules/send/index.js 29:9-22
Module not found: Error: Can't resolve 'fs' in '/Users/sebastianrichards/ReactProject/client/node_modules/send'

Answer 1

Try doing a clean install of npm by deleting /node_modules and running npm install. Also check that the package in the error exists within your package.json.

Answer 2

I solved it, I removed import { json } from 'express/lib/response'; from the imports on one of the react files and it worked