javascript – Can’t use Express.js in my React JS Project

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I’m trying to implement express.js into my react js Project, but when I add those two lines to my app.js code:

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

I am facing the following error:

ERROR in ./node_modules/body-parser/lib/read.js 19:11-26
Module not found: Error: Can't resolve 'zlib' in '[myReactProject]\node_modules\body-parser\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: { "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/body-parser/lib/types/urlencoded.js 201:12-34
Module not found: Error: Can't resolve 'querystring' in '[myReactProject]\node_modules\body-parser\lib\types'

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/content-disposition/index.js 21:15-39
Module not found: Error: Can't resolve 'path' in '[myReactProject]\node_modules\content-disposition'

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: { "path": require.resolve("path-browserify") }'
    - install 'path-browserify'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "path": false }
ERROR in ./node_modules/cookie-signature/index.js 5:13-30
Module not found: Error: Can't resolve 'crypto' in '[myReactProject]\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 '[myReactProject]\node_modules\destroy'
ERROR in ./node_modules/destroy/index.js 16:13-30
Module not found: Error: Can't resolve 'stream' in '[myReactProject]\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: { "stream": require.resolve("stream-browserify") }'
    - install 'stream-browserify'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "stream": false }
ERROR in ./node_modules/destroy/index.js 17:11-26
Module not found: Error: Can't resolve 'zlib' in '[myReactProject]\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 20:13-30
Module not found: Error: Can't resolve 'crypto' in '[myReactProject]\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 21:12-31
Module not found: Error: Can't resolve 'fs' in '[myReactProject]\node_modules\etag'
ERROR in ./node_modules/express/lib/application.js 22:11-26
Module not found: Error: Can't resolve 'http' in '[myReactProject]\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/application.js 29:14-37
Module not found: Error: Can't resolve 'path' in '[myReactProject]\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: { "path": require.resolve("path-browserify") }'
    - install 'path-browserify'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "path": false }
ERROR in ./node_modules/express/lib/request.js 17:11-30
Module not found: Error: Can't resolve 'net' in '[myReactProject]\node_modules\express\lib'
ERROR in ./node_modules/express/lib/request.js 19:11-26
Module not found: Error: Can't resolve 'http' in '[myReactProject]\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/response.js 20:11-26
Module not found: Error: Can't resolve 'http' in '[myReactProject]\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/response.js 23:11-26
Module not found: Error: Can't resolve 'path' in '[myReactProject]\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: { "path": require.resolve("path-browserify") }'
    - install 'path-browserify'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "path": false }
ERROR in ./node_modules/express/lib/utils.js 23:18-40
Module not found: Error: Can't resolve 'querystring' in '[myReactProject]\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/express/lib/view.js 16:11-26
Module not found: Error: Can't resolve 'path' in '[myReactProject]\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: { "path": require.resolve("path-browserify") }'
    - install 'path-browserify'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "path": false }
ERROR in ./node_modules/express/lib/view.js 17:9-22
Module not found: Error: Can't resolve 'fs' in '[myReactProject]\node_modules\express\lib'
ERROR in ./node_modules/mime-types/index.js 15:14-37
Module not found: Error: Can't resolve 'path' in '[myReactProject]\node_modules\mime-types'

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: { "path": require.resolve("path-browserify") }'
    - install 'path-browserify'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "path": false }
ERROR in ./node_modules/mime/mime.js 1:11-26
Module not found: Error: Can't resolve 'path' in '[myReactProject]\node_modules\mime'

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: { "path": require.resolve("path-browserify") }'
    - install 'path-browserify'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "path": false }
ERROR in ./node_modules/mime/mime.js 2:9-22
Module not found: Error: Can't resolve 'fs' in '[myReactProject]\node_modules\mime'
ERROR in ./node_modules/parseurl/index.js 14:10-24
Module not found: Error: Can't resolve 'url' in '[myReactProject]\node_modules\parseurl'

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: { "url": require.resolve("url/") }'
    - install 'url'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "url": false }
ERROR in ./node_modules/send/index.js 22:9-22
Module not found: Error: Can't resolve 'fs' in '[myReactProject]\node_modules\send'
ERROR in ./node_modules/send/index.js 27:11-26
Module not found: Error: Can't resolve 'path' in '[myReactProject]\node_modules\send'

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: { "path": require.resolve("path-browserify") }'
    - install 'path-browserify'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "path": false }
ERROR in ./node_modules/send/index.js 29:13-30
Module not found: Error: Can't resolve 'stream' in '[myReactProject]\node_modules\send'

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: { "stream": require.resolve("stream-browserify") }'
    - install 'stream-browserify'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "stream": false }
ERROR in ./node_modules/send/index.js 30:11-26
Module not found: Error: Can't resolve 'util' in '[myReactProject]\node_modules\send'

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: { "util": require.resolve("util/") }'
    - install 'util'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "util": false }
ERROR in ./node_modules/serve-static/index.js 18:14-37
Module not found: Error: Can't resolve 'path' in '[myReactProject]\node_modules\serve-static'

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: { "path": require.resolve("path-browserify") }'
    - install 'path-browserify'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "path": false }
ERROR in ./node_modules/serve-static/index.js 20:10-24
Module not found: Error: Can't resolve 'url' in '[myReactProject]\node_modules\serve-static'

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: { "url": require.resolve("url/") }'
    - install 'url'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "url": false }

How to recreate this Problem:

  • start by creating a new react project via the “create-react-app” command
  • install express using npm/yarn
  • add “const express = require(‘express’)” and “const app = express()” to app.js

What I’ve already tried:

  • included polyfills via (for Example): resolve.fallback: { “zlib”: false } for every dependency listed in the error
  • installing every dependency seperatly

Read more here: Source link