Support .env file for production / preview node preset

[pi0]

It is quite often required to test production Node.js preset outputs with dotenv file. I am thinking of 3 possible ways:

• Change preview command to node -r require/dotenv .output/server/index.mjs (user needs dotenv local dependency)
• Support a preview command used by nitro (and other frameworks such as nuxi)
• Enable feature by default (as a bundled runtime)
• Enable feature behind a flag (can be enabled by a CLI flag)

Need to check how much is actual runtime overhead of dotenv (it seems as low as 5KB).

Also worth to node that, the "local" kind presets (Bun and Deno) both already have built-in dotenv support via CLI args. And there is an ongoing discussion within Node.js team to make it build-in feature..

[Hebilicious]

For cloudflare presets previews, there's builtin dotenv supports too, but the file needs to be named .dev.vars

[pi0]

Good to know! My aim for this issue was mainly for Node presets but having other preset previews in mind, we might either leverage possible preview command or guide with args to use .env

[gyhyfj]

Currently, append --dotenv .env.local to dev or build script doesn't work like nuxt, is it?

[danielroe]

Note that this feature should be coming to Node natively in 20.6.

nodejs/node#49185

[gyhyfj]

what if running in serverless environment rather than node server in future?

[Hebilicious]

Note that this feature should be coming to Node natively in 20.6.

nodejs/node#49185

Turns out the strong competition provided by deno and bun is working. We might have TS support in node at this rate 🤞🏽

[Gonzalo-Bruna]

Hi! Could this behavior be clarified or added to the Nitro documentation?

I’ve spent hours trying to figure out why .env variables work perfectly in the development environment but not in the production build. Despite trying several approaches, I still can’t get it to work. Here’s what I’ve done:

1. Installed dotenv and attempted to run the server with the following command:

   node -r dotenv/config .output/server/index.mjs

2. Placed the .env file in both the .output directory and the .output/server directory.

3. Installed Node.js version 22 because I read that Node.js now supports .env files natively since version 20.6. However, the .env variables still don’t load.

It would be really helpful to have clear guidance on how to properly handle .env variables in the production build (for local testing or deployment), especially since this seems like a common issue. Thank you for your time!

[saike]

for me this works for now:
node -r dotenv/config .output/server/index.mjs