In this blog we will discuss how we use a specific env file such as .env.trail , .env.test , .env.prod etc to use in our apllication. As per many projects the requirement will be that for a specific environment the Secret Keys or Tokens or some URLs in env file must differ. But by default few frameworks supports .env.test , .env.production , .env.development. So what if your project has multiple other environments such as stage, trail, pre-prod etc...

For this we can create our env files with suffix with environment name such as .env.prod, then we need an package which will configure the specific env file while runtime.

JWT_TOKEN = qwertyuiop
LOGIN_URL_CALLBACK = test.url.com

JWT_TOKEN = abcdefghijk
LOGIN_URL_CALLBACK = dev.url.com

So we can use popular npm package called <a href="https://www.npmjs.com/package/env-cmd" >env-cmd</a> which can be installed to your project by the npm command.

npm i env-cmd

Once the package is installed you can add scripts in package.json to use specific env for specific environments.

{
    "scripts": {
       ... ,
       "test-deploy" : "env-cmd -f .env.test npm run build && npm run start",
       "dev-start" : "env-cmd -f .env.development npm run dev",
       "dev-deploy" : "env-cmd -f .env.development npm run build && npm run start"
    }
}

Now when you start application in a specific environment, use the script mentioned in package.json file as npm run dev-start which will start the dev server with .env.development file as env config file. Also you can run npm run test-deploy which will take the env file as env.test before building & starting the production server. So this can be helpul for usage of multiple env files in multiple environments and you can add scripts based on your needs.