install-logger

A tiny demo package that prints a message to the console when it's installed, using npm's postinstall lifecycle hook.

How it works

package.json defines several install-time lifecycle hooks:

"scripts": {
  "preinstall": "node lifecycle.js",
  "install": "node lifecycle.js",
  "postinstall": "node lifecycle.js",
  "prepare": "node lifecycle.js"
}

When the package is installed as a dependency, npm runs these hooks in order (preinstall → install → postinstall, plus prepare for git/local/link installs). lifecycle.js reads npm_lifecycle_event and console.logs which hook fired.

Why postinstall might not run

Not every package manager runs dependency lifecycle scripts. Bun and pnpm block them by default for security and only run them for packages you explicitly trust:

• Bun: add the package to trustedDependencies in the installing project's package.json, then reinstall. Without it, none of these hooks run.
• pnpm (v10+): approve with pnpm approve-builds, or list the package under pnpm.onlyBuiltDependencies.
• npm: runs them by default unless --ignore-scripts is set.

Try it locally (without publishing)

# from another folder
npm install /path/to/install-logger

You'll see the install message printed.

Publishing

1. Change name in package.json to something unique (or keep the @yourusername scope and swap in your npm username).
2. npm login
3. npm publish --access public