Different env variables for testing and development in nodejs

Question

I'm developing a nodejs api in my free time, and I'm trying to implement testing now. I'm currently loading my environment variables from a .env file (loaded using dotenv), which include the DB_URI, DB_USER and DB_PASSWORD for my development mongodb database.

Now, I would like to create a separate database for testing however I don't know how would I load different variables to connect to the testing database instead of the development database. I deploy to Heroku where I have different environment variables so that's covered just fine.

I've tried to find online for some answers for best practices, but I have been unable to. I thought of creating a different .env file, however that's not recommended according to the documentation on npmjs..

Other resources recommended recommended hard coding the specific variables I needed in the package.json script. However, the script would be huge if I had to change all the variables needed to connect to a different database.

Can I get some help understanding how I should do this?

Thanks!

PS: In case it's needed, I'm using mocha and supertest for my tests.

Answer 1

You can use the dotenv package as follows:

1. In your .env file, add variables for each environment:

   DB_URI_DEVELOPMENT="https://someuri.com"
   DB_USER_DEVELOPMENT=someuser
   DB_PASSWORD_DEVELOPMENT=somepassword
   
   DB_URI_TEST="https://otheruri.com"
   DB_USER_TEST=otheruser
   DB_PASSWORD_TEST=otherpassword
   

2. Start the application in development:

    NODE_ENV=development node server.js
   

   or in test:

    NODE_ENV=test node server.js
   

3. Access the environment variables in your app:

   /**
    * This `if` block prevents loading of the .env file on Heroku by calling
    * dotenv.config() if and only if `NODE_ENV` is not equal to "production"
    *  
    * In order to set environment variables on Heroku, use "config vars":
    * @see {@link https://devcenter.heroku.com/articles/config-vars}.
    *
    * If you must use `dotenv` to load an .env file on Heroku, follow:
    * @see {@link https://stackoverflow.com/a/54884602/1526037}.
    */
   if (process.env.NODE_ENV !== 'production') {
     require('dotenv').config();
   }
   
   // Get the current environment, and convert to uppercase (e.g. "PRODUCTION").
   const env = process.env.NODE_ENV.toUpperCase();
   
   // Access the environment variables for the current environment
   // by postfixing them with the uppercase environment string.
   const {
     [`DB_URI_${env}`]: dbUri,
     [`DB_USER_${env}`]: dbUser,
     [`DB_PASSWORD_${env}`]: dbPassword,
   } = process.env;
   
   /*
    * Note, the above is the same as:
    * ---------------------------------------------------------
    * var dbUri = process.env['DB_URI_' + env];
    * var dbUser = process.env['DB_USER_' + env];
    * var dbPassword = process.env['DB_PASSWORD_' + env];
    */