Bun v1.0.0 --production flag and optionalDependencies pruning

Answer to the Core Questions

**1. Optional Dependencies** – Bun v1.0.0 does not expose a flag or configuration to skip optionalDependencies when running bun install --production. All optional dependencies listed in package.json are installed by default, and the current CLI options do not include a --no-optional or similar switch.

**2. Peer Dependencies** – Bun also does not automatically prune peerDependencies in a production install. Peer dependencies are treated the same as normal dependencies if they are present in package.json; otherwise they are not installed unless required by a transitive dependency. There is no built‑in command to strip them out.

Practical Work‑Arounds

While Bun lacks dedicated flags, you can still achieve a lean node_modules tree with the following routine:

1. Run a normal production install:

   bun install --production
   

2. Identify optional and peer packages that are not needed by your runtime. A quick audit can be done with:

   find node_modules -maxdepth 1 -type d -printf "%f\n" | grep -E "^optional|^peer"
   

3. Remove unwanted directories manually or via a script. For example:

   rm -rf node_modules/optional-package
   rm -rf node_modules/peer-package
   

4. Optionally run bun prune to clean up any extraneous packages that are no longer listed in package.json:

   bun prune
   

For larger projects, consider a small Node or Bun script that parses package.json, removes entries under optionalDependencies and peerDependencies, writes the cleaned file, and then runs bun install --production again. This keeps your source intact while producing a minimal install.

Verification Steps

• Run bun install --help to confirm that no --no-optional flag exists.
• After installation, list installed packages with bun ls --depth=0 and compare against package.json to ensure no unwanted optional or peer packages remain.
• Test the application in a container or serverless environment to confirm that startup latency and disk usage have improved.

Future Outlook

The Bun team has indicated that future releases may add flags such as --no-optional or automated peer pruning, but these are not present in v1.0.0. Staying on v1.0.0 means you’ll need to apply the manual approach described above.

One Diagnostic Question

Do you know if any of your modules rely on optional or peer dependencies at runtime? Identifying those will help you decide which packages can safely be removed.