Adding an .env file to a React project [duplicate]

Four steps

1. npm install dotenv --save

2. Next, add the following line to your app.

   require('dotenv').config()

3. Then create a .env file at the root directory of your application and add the variables to it.

// contents of .env

REACT_APP_API_KEY = 'my-secret-api-key'

4. Finally, add .env to your .gitignore file so that Git ignores it and it never ends up on GitHub.

If you are using Create React App (create-react-app) then you only need step 3 and 4, but keep in mind a variable needs to start with REACT_APP_ for it to work.

Reference: Adding Custom Environment Variables

Note – You need to restart the application after adding a variable in the .env file.

Reference: Using the dotenv package to create environment variables