Chris Weekly

UI Architect & Web Performance Consultant

Mar 17, 2022

Hi Blaine Garrett,
Thanks for sharing a great writeup about a gnarly topic.

I have a minor correction to share. You wrote:

"Note: This hierarchy optionally goes further with .env.development and .env.production (corresponding to the value of NODE_ENV)..."

But they don't actually correspond to the value of NODE_ENV. Next.JS bases its decision to read from .env.development vs .env.production on one thing only: whether you start the app with next dev or next start. That's all. NODE_ENV's value is irrelevant to that bit of Next-specific logic.

AFAICT you get the rest of the complicated picture right; hopefully my comment will inspire you to edit the post, or at least help ensure other readers aren't accidentally misled.

Slainte, Chris

Blaine Garrett

Software Engineer and Artist

Mar 18, 2022

Thanks Chris! I made the correction.

However, now that I reread the loading order docs, I'm conflicted if this is accurate. nextjs.org/docs/basic-features/environment-variab…

Again, I don't use this feature often so I hesitate to dig further at the moment. I tend to explicitly add the NODE_ENV to my command line args when running the prod build locally but it might be redundant in that next dev is implicitly NODE_ENV='development' and next start is NODE_ENV='production'. I'm tempted to see what NODE_ENV='development' next start produces. I'll have to try it out later. Anywho, thanks again for commenting and I'm glad these articles are still helping folks out after 2 years.

Right on, Blaine Garrett.

FTR I did exhaustive tests including NODE_ENV=development next start, NODE_ENV=production next dev, etc -- but I'm also currently stuck on v10.2.3. Maybe this has since changed in v11 or v12.

IMHO Next.js made a rare misstep in being both opinionated and rigid about proper support for true 12-factor config that lives in the runtime deploy environment. It probably stems from their original desire to stay "close" to create-react-app, and ofc whatever most closely aligns with Vercel's preferred hosting model. (shrug)

Slainte,
Chris

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