Cannot find module '@babel/core'

Try running this.

npm install @babel/core --save

babel changed their package so your babel-core will not be the same as @babel/core.

The recent Babel upgrade to version 7 changed the namings of the node packages.

For instance, now you have to install

npm install --save-dev @babel/core @babel/preset-env

and

npm install --save-dev @babel/preset-react

to get it working with React. Then you can use these in your .babelrc file:

{
  "presets": [
    "@babel/preset-env",
    "@babel/preset-react"
  ]
}

Or as alternative, when not having a .babelrc, in your package.json:

...
"keywords": [],
"author": "",
"license": "ISC",
"babel": {
  "presets": [
    "@babel/preset-env",
    "@babel/preset-react"
  ]
},
"devDependencies": {
...

If you want to get more into it, you can checkout this recent Webpack + Babel + React setup.

I removed the existing npm uninstall babel-core babel-preset-env babel-preset-react

and added their new names npm install --save-dev @babel/core @babel/preset-env @babel/preset-react that's works for me as perfectly fine.

for those of you who use @babel/core alongside babel-node: i just installed @babel/core using npm i @babel/core --save-dev but when i tried to use babel-node it does not recognized the @babel/core package, i uninstalled @babel/core and installed it again using npm i @babel/core --save and it worked again!

In my case I had to uninstall babel 6

npm uninstall --save-dev babel-cli  babel-core babel-polyfill babel-preset-es2015 babel-preset-stage-2 babel-register

and then reinstall babel 7

npm i  --save-dev  @babel/cli  @babel/core @babel/node  @babel/polyfill  @babel/preset-env

and it worked for me.

I am able to fix this issue using below command

npm install @babel/core --save

babel-loader@8 requires Babel 7.x (the package '@babel/core'). If you'd like to use Babel 6.x ('babel-core'), you should install 'babel-loader@7'.

try to install npm install @babel/core --save if it does not work try to uninstall node_modules and reinstall

I solved the same error by removing all the babel modules from dev Dependencies executing the below command:

npm install -D babel-loader @babel/core @babel/preset-env

You can refer to this link if the above command does not work:

[https://github.com/babel/babel/issues/8599#issuecomment-417866691]

I fixed with:

 npm install --save-dev babel-loader@7 babel-core babel-preset-env webpack webpack-cli -D

I've been dealing with this problem for a few hours and it mysteriously disappeared when I added a "devDependencies" section to my package.json file and moved the @types dependencies to it.

if you have react application and you get error change your babel config to below:

 {
"presets": [
    [
        "@babel/preset-env",
        {
            "useBuiltIns": "entry",
            "corejs": 3,
            "modules": false
        }
    ],
    "@babel/preset-react"
],
"plugins": [
    ["@babel/transform-async-to-generator"],
    ["@babel/plugin-transform-runtime"],
    ["@babel/syntax-dynamic-import"],
    ["@babel/plugin-transform-classes", {
    "loose": true
    }],
    [
        "babel-plugin-transform-builtin-extend",
        {
            "globals": ["Error"]
        }
    ]
]

}

my two cents, for people getting started with react, webpack, babel, jsx, I got a problem with npm run build

ERROR in ./src/app.js
Module build failed (from ./node_modules/babel-loader/lib/index.js):
Error: Cannot find module 'babel-core'

When you tried to gradually install each component, you might run into a version conflict between packages, i.e., you might ended up with a package.json file like this

  "dependencies": {
    "@babel/core": "^7.13.15",
    "@babel/preset-env": "^7.13.15",
    "@babel/preset-react": "^7.13.13",
    "babel-loader": "^7.1.5",
    "webpack": "^5.33.2",
    "webpack-cli": "^4.6.0"

Clearly, the reported failed to load babel-loader is not because I did not have babel-loader installed. Therefore, I think, I would try to re-install it again with npm i babel-loader.

And, I got this message

$ npm install babel-loader
npm ERR! code ERESOLVE
npm ERR! ERESOLVE unable to resolve dependency tree
npm ERR! 
npm ERR! While resolving: indecision-app@1.0.0
npm ERR! Found: webpack@5.33.2
npm ERR! node_modules/webpack
npm ERR!   webpack@"^5.33.2" from the root project
npm ERR! 
npm ERR! Could not resolve dependency:
npm ERR! peer webpack@"2 || 3 || 4" from babel-loader@7.1.5
npm ERR! node_modules/babel-loader
npm ERR!   babel-loader@"^7.1.5" from the root project

I noticed that I'm using Webpack v.5. Hence, I remove babel-loader from package.json file and do npm i babel-loader again.

This time, npm run build was successful!

Go in by running on Windows, %USERPROFILE%\.quokka

The ~/.quokka configuration is limited to the config.json file and any packages that exist in ~/quokka/node_modules.

Put the following into config.js,

{
  "pro":true, 
  "babel": {
    "presets": ["@babel/preset-env", " @babel/preset-react"],
    "plugins": [
      ["@babel/plugin-proposal-pipeline-operator", { "proposal": "minimal" }],
      ["@babel/plugin-proposal-decorators", { "legacy": true }],
      ["@babel/plugin-proposal-class-properties", { "loose": true }]
    ]
  }
}