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.

sbolel · Answer 1 · 2021-09-17T20:11:05.837

You can use the dotenv package as follows:

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

Start the application in development:

 NODE_ENV=development node server.js

or in test:

 NODE_ENV=test node server.js

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];
 */

Yes it is @Enrique. For Heroku, you have two options for defining environment variables. 1) you can use `dotenv` only locally, and for production, define ["config vars"](https://devcenter.heroku.com/articles/config-vars) in the Heroku interface and access them in your app as environment variables (`process.env`), or (2) you can use `dotenv` in production as well, by following [the directions in this answer](https://stackoverflow.com/a/54884602/1526037). — sbolel, Sep 17 '21 at 19:45

score 0 · Answer 2 · answered Sep 29 '22 at 21:56

Personally I like having the same environment variable names for different environments, so I created a env.ts to include where I want to load my dotEnv so I can use the same environment variable names throughout my application.

import * as process from "process";
import * as dotenv from 'dotenv'
import * as path from "path";

const getDotEnvPath = (env?: string) => {
    if (env == 'TEST') {
        return '.env.test'
    }
    return '.env'
}
dotenv.config({path: path.resolve(process.cwd(), getDotEnvPath(process.env.NODE_ENV?.toUpperCase()))})

Its also good to note that by default dotEnv only sets the environment variables when they are not already set.

Different env variables for testing and development in nodejs

2 Answers2