Um...seems to be a bug, user options is loaded before NODE_ENV initialized.

We might have an architectural issue here. The build command (which is setting the production mode) is implemented as a plugin (like all other commands), and plugins receive the loaded config in their arguments - so the config has to be loaded before the build command can be run.

This might not be a simple change this line type of bugfix.

As a workaround, I remember putting NODE_ENV=production in front of the existing build command

@LinusBorg , Yes, I managed to find a clean fix and realized it's not that simple...Actually we can pass all user arguments in to Service when calling its constructor. However commands like serve and build have their own default arguments, which can not simply be touched during Service initialize stage.

As a workaround at the moment I'm using process.env.npm_lifecycle_event === 'build' to differentiate between dev/build.

I'm using a similar way as @xvaara but match the process.env.npm_lifecycle_script to get the mode value, and use Dotenv to load the .env.[mode] file at the vue.config.js 's beginning.