1. make sure you dont already have eslint installed in your project (uninstall it first if you do)

2. install package npm i JohnDeved/undefined-lint

3. create .eslintrc file in your project root

{
    "extends": [
        "./node_modules/@undefined/lint/.eslintrc"
    ]
}

4. check if you are running node 16. eslint is required to run on node 16. you may have to add "eslint.runtime": "node", in your vscode settings for eslint to use your local node16 installation.

recommended workspace settings .vscode/settings.json:

{
    "eslint.runtime": "node",
    "editor.tabSize": 2,
    "editor.codeActionsOnSave": {
      "source.fixAll.eslint": true,
      "source.fixAll.stylelint": true
    }
}