Cannot resolve module 'react-dom'

In my case I had an alias in my webpack.config.common.js:

 resolve: {
    extensions: ['.js', '.jsx'],
    alias: {
      'react-dom': '@hot-loader/react-dom',
    },
  },

I just removed this line:

'react-dom': '@hot-loader/react-dom',

and it was fixed.

Issue is react-dom is not installed, when you hit npm -v react-dom, it gives you the version of npm not react-dom version, you can check that by using npm -v or npm -v react-dom both will give you the same result. You are checking the package version incorrectly.

How to install react and react-dom properly?

Use this to install react and react-dom:

npm install react react-dom --save

After that, you can check your package.json file, if react and react-dom has been installed correctly, you will find an entry for that.

How to check install package version?

To check all the locally installed packages version:

npm list    

For globally installed packages, use -g also:

npm list -g

To check the version of any specific package, specify the package name also:

npm list PackageName

For Example =>
   npm list react
   npm list react-router

After installation your package.json will look like this:

{
  "name": "***",
  "version": "1.0.0",
  "main": "***",
  "scripts": {
     ....
  },
  "repository": {
     ....
  },
  "keywords": [],
  "author": "",
  "dependencies": {
    ....
    "react": "^15.4.2",          //react
    "react-dom": "^15.4.2",      //react-dom
     ....
  },
  "devDependencies": {
     ....
  }
}

Latest version of react-dom is : 15.4.2

Reference: https://www.npmjs.com/package/react-dom