[npm] Module not found: Error: Can't resolve 'core-js/es6'

I've got a problem with my build process in relation to my React app.

I always get the following error:

Module not found: Error: Can't resolve 'core-js/es6'

if I use this in a polyfill.js:

import 'core-js/es6';

That is my package.json:

{_x000D_
  "name": "test",_x000D_
  "version": "1.0.0",_x000D_
  "main": "index.js",_x000D_
  "license": "MIT",_x000D_
  "private": true,_x000D_
  "devDependencies": {_x000D_
    "@babel/core": "^7.4.0",_x000D_
    "@babel/preset-env": "^7.4.2",_x000D_
    "@babel/preset-react": "^7.0.0",_x000D_
    "@babel/runtime": "^7.4.2",_x000D_
    "babel-loader": "^8.0.5",_x000D_
    "babel-preset-es2015": "^6.24.1",_x000D_
    "copy-webpack-plugin": "^5.0.2",_x000D_
    "css-hot-loader": "^1.4.4",_x000D_
    "eslint": "5.15.3",_x000D_
    "eslint-config-airbnb": "^17.1.0",_x000D_
    "eslint-loader": "^2.1.2",_x000D_
    "eslint-plugin-import": "2.16.0",_x000D_
    "eslint-plugin-jsx-a11y": "6.2.1",_x000D_
    "eslint-plugin-react": "7.12.4",_x000D_
    "file-loader": "^3.0.1",_x000D_
    "node-sass": "^4.11.0",_x000D_
    "prettier": "^1.16.4",_x000D_
    "react-hot-loader": "4.8.0",_x000D_
    "sass-loader": "^7.1.0",_x000D_
    "webpack": "^4.29.6",_x000D_
    "webpack-cli": "^3.3.0",_x000D_
    "webpack-dev-server": "^3.2.1"_x000D_
  },_x000D_
  "dependencies": {_x000D_
    "axios": "^0.18.0",_x000D_
    "core-js": "^3.0.0",_x000D_
    "prop-types": "^15.7.2",_x000D_
    "react": "^16.8.5",_x000D_
    "react-dom": "^16.8.5",_x000D_
    "react-redux": "^6.0.1",_x000D_
    "react-string-replace": "^0.4.1",_x000D_
    "redux": "^4.0.1",_x000D_
    "slick-carousel": "^1.8.1"_x000D_
  },_x000D_
  "scripts": {_x000D_
    "dev": "webpack-dev-server --hot",_x000D_
    "build": "webpack --colors --profile --progress --env.mode production",_x000D_
    "lint": "eslint ./src/ --ext .js,.jsx"_x000D_
  }_x000D_
}

Can someone help here?

After Migrated to Angular8, core-js/es6 or core-js/es7 Will not work.

You have to simply replace import core-js/es/

For ex.

import 'core-js/es6/symbol'  

to

import 'core-js/es/symbol'

This will work properly.

Just change "target": "es2015" to "target": "es5" in your tsconfig.json.

Work for me with Angular 8.2.XX

Tested on IE11 and Edge

The imports have changed for core-js version 3.0.1 - for example

import 'core-js/es6/array'; and import 'core-js/es7/array';

can now be provided simply by the following

import 'core-js/es/array';

if you would prefer not to bring in the whole of core-js

Change all "es6" and "es7" to "es" in your polyfills.ts and polyfills.ts (Optional).

• From: import 'core-js/es6/symbol';
• To: import 'core-js/es/symbol';

I found possible answer. You have core-js version 3.0, and this version doesn't have separate folders for ES6 and ES7; that's why the application cannot find correct paths.

To resolve this error, you can downgrade the core-js version to 2.5.7. This version produces correct catalogs structure, with separate ES6 and ES7 folders.

To downgrade the version, simply run:

npm i -S [email protected]

In my case, with Angular, this works ok.

Change all "es6" and "es7" to "es" in your polyfills.ts and polyfills.ts

Sure, I had a similar issue and a simple

npm uninstall @babel/polyfill --save &&
npm install @babel/polyfill --save

did the trick for me.

However, usage of @babel/polyfill is deprecated (according to this comment) so only try this if you think you have older packages installed or if all else fails.

If you use @babel/preset-env and useBuiltIns, then you just have to add corejs: 3 beside the useBuiltIns option, to specify which version to use, default is corejs: 2.

presets: [
  [
    "@babel/preset-env", {
      "useBuiltIns": "usage",
      "corejs": 3
    }
  ]
],

For further details see: https://github.com/zloirock/core-js/blob/master/docs/2019-03-19-core-js-3-babel-and-a-look-into-the-future.md#babelpreset-env