Why I should not use dotenv in production mode ?
I saw the following code on some websites. But I did not understand why they are doing this condition check.
if (process.env.NODE_ENV !== 'production') {
require('dotenv').config();
}
console.log('Bla is :', process.env.Bla);(*)
let assume that the output of the line(*) in not production mode is-> Bla is : Bla
what is the output of line (*) if the NODE_ENV is production? (According to my knowledge I think it will be undefined )
Because in production, you might want to set the environment variables directly into your virtual machine, as you might not have ssh access and you can't push .env file to your version control. In my case I'm using heroku free tier and I can't ssh to create a .env file. So I set my environment variables manually in the Config Vars settings.
Complementing the other answers, you would also create a security issue. You would be versioning (commiting to git) informations like database connections, tokens, and passwords. In this case everyone who access the code, would be able to connect to production resources.
To solve this, on production you create the env variables directly on the instance you are running the code.
The idea behind this is that dotenv is generally used on a developer workstation. It is a way of using a flat file (usually named ".env") to override environment files. The reason you dont use it in production is that in production you would usually be running the application in a docker container or a dedicated server, either of which, you wouldnt need to worry about setting conflicting environment variables.
To answer the actual question, the output for that line in this case would be whatever that local environment variable is set to. If its not set, it would just be undefined.
In this example, its preference of the developer. There's nothing stopping you from using it, but in production you likely have set up all the needed environment variables.
Here, they use dotenv during testing and development. This allows the developer to define their environment variables in .env files while they write the app which would be useful for preventing working on the wrong database.
So think of it like this:
When developing or testing the code, use the test keys, otherwise, use the keys provided by the environment
If the environment variable Bla wasn't set up prior to running Node, then it would be undefined, but it is likely configured to be whatever production values this code needs like an email or API key.