Follow the peer deps down each package in a monorepo

peer-dep-stuff.cjs

#!/usr/bin/env node

// NOTE: I forgot to have it traverse dependencies as well as dev dependencies. 
// Really, it should check both if we're going to have a clean set of peer dependencies for a published package.
const { getPackages } = require('@manypkg/get-packages')
const process = require('node:process')
const path = require('node:path')

const ROOT_DIR = process.cwd()

function getPeerDependencies(depName, dir, accumPeerDeps, indent = '') {
  const location = require.resolve(`${depName}/package.json`, {
    paths: [dir],
  })

  const { name, peerDependencies = {} } = require(location)
  const peerDeps = Object.entries(peerDependencies)
  for (const [dep, version] of peerDeps) {
    accumPeerDeps.add(`${dep}:${version}`)
    console.log(`${indent}  - ${dep}:${version}`)
    getPeerDependencies(
      dep,
      path.dirname(location),
      accumPeerDeps,
      indent + '  '
    )
  }
}

async function run() {
  const { packages } = await getPackages(ROOT_DIR)

  for (const pkg of packages) {
    const { dir, packageJson } = pkg
    const { name, peerDependencies = {} } = packageJson

    console.log(`-- ${name} --`)
    const peerDeps = Object.entries(peerDependencies)
    const accumPeerDeps = new Set()
    const indent = ''
    for (const [dep, version] of peerDeps) {
      accumPeerDeps.add(`${dep}:${version}`)
      console.log(`${indent}  - ${dep}:${version}`)
      getPeerDependencies(dep, dir, accumPeerDeps, indent + '  ')
    }
    console.log(`** ACCUMULATED PEER DEPS **`)
    for (const accumDep of accumPeerDeps) {
      console.log(`  * ${accumDep}`)
    }
  }
}

run()