astro/.changeset/sixty-coins-worry.md

astro
minor

Adds support for passing values other than "production" or "development" to the --mode flag (e.g. "staging", "testing", or any custom value) to change the value of import.meta.env.MODE or the loaded .env file. This allows you take advantage of Vite's mode feature.

Also adds a new --devOutput flag for astro build that will output a development-based build.

Note that changing the mode does not change the kind of code transform handled by Vite and Astro:

• In astro dev, Astro will transform code with debug information.
• In astro build, Astro will transform code with the most optimized output and removes debug information.
• In astro build --devOutput (new flag), Astro will transform code with debug information like in astro dev.

This enables various usecases like:

# Run the dev server connected to a "staging" API
astro dev --mode staging

# Build a site that connects to a "staging" API
astro build --mode staging

# Build a site that connects to a "production" API with additional debug information
astro build --devOutput

# Build a site that connects to a "testing" API
astro build --mode testing

The different modes can be used to load different .env files, e.g. .env.staging or .env.production, which can be customized for each environment, for example with different API_URL environment variable values.