dev-tweak-serve-package-json

dev-tweak-serve-package-json

Tweak serving-related commands in package.json. Requires --kill and/or --net flag.

Workflow

1. Read the project's package.json
2. Identify all serve/dev commands (scripts that start local servers — dev, serve, preview, start, etc.)
3. Detect the port(s) used by each command
4. Detect the framework (Next.js, Astro, Vite, etc.) from package.json dependencies
5. Apply the requested tweaks

--kill flag

Add port-killing before serve commands so stale processes don't block startup.

Pattern

For each serve command, detect the port it uses and add a preXXX script that kills it:

"predev": "lsof -ti :PORT | xargs kill 2>/dev/null; true",
"dev": "astro dev",

• Use preXXX npm lifecycle hook naming (e.g., predev for dev, preserve for serve)
• The kill command pattern: lsof -ti :PORT | xargs kill 2>/dev/null; true
• If a preXXX script already exists, prepend the kill command to it
• If the port is not obvious from the command, check common framework defaults (Astro: 4321, Next.js: 3000, Vite: 5173, etc.)

Port detection priority

1. Explicit -p PORT or --port PORT flag in the command
2. Framework default port from dependencies

--net flag

Create :net suffixed variants of serve commands that bind to 0.0.0.0 for LAN access.

Pattern

For each serve command, create a COMMAND:net variant:

"dev": "astro dev",
"dev:net": "astro dev --host 0.0.0.0",

Framework-specific host flags

Framework	Flag
Astro	--host 0.0.0.0
Next.js	-H 0.0.0.0
Vite / Vitest	--host 0.0.0.0
Webpack Dev Server	--host 0.0.0.0
serve (npm)	-l tcp://0.0.0.0:PORT or --listen tcp://0.0.0.0:PORT
http-server	-a 0.0.0.0
Docusaurus	--host 0.0.0.0

• Place the :net variant immediately after the original command
• If the command already has a host flag, replace it with 0.0.0.0
• If --kill is also specified, the :net variant should also get a matching preXXX:net kill script

Both flags together

When both --kill and --net are specified, apply both tweaks. Example result:

"predev": "lsof -ti :4321 | xargs kill 2>/dev/null; true",
"dev": "astro dev",
"predev:net": "lsof -ti :4321 | xargs kill 2>/dev/null; true",
"dev:net": "astro dev --host 0.0.0.0",

Important

• Only modify scripts that actually start servers (dev, serve, preview, start and their variants)
• Do not touch build, test, lint, or other non-server scripts
• Preserve existing script order — insert new scripts adjacent to their originals
• If the argument is missing or invalid, ask the user which flag(s) to apply