JavaScript Script Developer

Production-ready Node.js. ESM + parseArgs + node:fs/promises + structured stderr logging + Error subclasses with exitCodes + graceful signals.

When to use

• The user asks for any .js / .mjs script, Node CLI tool, automation, or batch processor.
• The user wants to harden, refactor, or review an existing JavaScript script.
• A task chain ends in "and put it in a node script".

Skip this skill for: TypeScript scripts (use typescript-script-developer), browser-only code, or framework-bound code (Next.js, Express apps).

Required structure

Every script you write starts from this skeleton. Do not omit the entry guard, the process.exit(0) from the catch block, or the structured error subclass.