ESLint - 'process' is not defined

Thanks @FelixKling and @Jaromanda X for quick responses.

I have fixed this with following config for .eslintrc.json file-

{    "env": {        "node": true,        "commonjs": true    },    "extends": "eslint:recommended",    "rules": {        "indent": [            "error",            "tab"        ],        "linebreak-style": [            "error",            "unix"        ],        "quotes": [            "error",            "single"        ],        "semi": [            "error",            "always"        ]    },    "parserOptions": {        "ecmaVersion": 2015    }}

When I got error I had "browser": true instead of "node": true. Simple mistake.

Adding "node": "true" to an existing list of environments will do the job, too

"env": {        "node": true,        "commonjs": true,        "browser": true,        "es6": true       }

Add .eslintrc file to root of your project (if you don't already have one) and define globals to ignore

{    "globals": {        "process": true      }}

Make sure you use process.env though out the project but only in a single configuration file. Consider adding no-process-envrule.

https://eslint.org/docs/rules/no-process-env