performance impact of reading process.env.X

[didiercolens]

reading environment variables from process.env is expensive and slow according to:

• Cache accesses to process.env? nodejs/node#3104
• https://www.reddit.com/r/node/comments/7thtlv/performance_penalty_of_accessing_env_variables/
• https://expressjs.com/en/advanced/best-practice-performance.html

it looks like the behaviour is still the same in recent nodejs, should user prefer using dotenv.config().parsed.X over process.env.X in highly use code paths ?

[yauri-io]

@didiercolens one solution is convert all of your .env content into a single .js file.

For example
.env

SERVER_HOST=0.0.0.0
SERVER_PORT=3000
SECRET=ANY_SECRET_STRING

config.js

module.exports = {
    server: {
        host: process.env.SERVER_HOST,
        port: process.env.SERVER_PORT
    },
    secret: process.env.SECRET
}

Then require the config.js in any place you want to use

[motdotla]

Thank you for posting this. It is interesting. I've decided it is beyond the scope of this module though. We are trying to keep things as simple as possible.

We'd recommend to still use process.env since that works across environments.