Duplicate environment config with pm2

I've been using Node v20, passing it --env-file .env.dev in order to set environment variables.

Now, for some package scripts I need to add pm2 support. I see that pm2 forces me to place environment variables into ecosystem.config.js.

Now I have 2 copies of environment variables, ones to be used by pure NodeJS scripts, and ones used by PM2 scripts. I would think that PM2 should be smarter than that, and let us reuse what NodeJS supports natively, but I haven't been able to find how.

Is there a way to avoid duplication of environment configuration in this scenario? I really do not want to maintain environment config in 2 places because of PM2.

My package scripts now look like this:

    "start": "tsc && node --env-file .env.dev ./src/index.js channel=primary",
    "start-dev": "pm2 start ecosystem.config.js --env dev",
    "start-prod": "pm2 start ecosystem.config.js --env prod",

And so now I have to maintain the same environment variables inside .env.dev file, plus inside ecosystem.config.js file, which isn't good maintenance-wise.

Start by reading the package scripts, .env.dev, and ecosystem.config.js, then inspect PM2's environment-loading and process-start entry points alongside Node's --env-file behavior. Done means the documented PM2 workflow can reuse one environment configuration without maintaining duplicate variables, with the relevant behavior covered by tests.