remove-transitive.js

const fs = require('fs')
const lockfile = require('@yarnpkg/lockfile')
const package = require('./package.json')

const lock = lockfile.parse(fs.readFileSync('yarn.lock', 'utf-8')).object

const allDeps = new Set()

const parseDep = ([name, version]) => {
  allDeps.add(`${name}@${version}`)
}

Object.entries(package.dependencies).forEach(parseDep)
Object.entries(package.devDependencies).forEach(parseDep)

const newLock = Object.fromEntries(Object.entries(lock).filter(([dep]) => allDeps.has(dep)))
const newLockString = lockfile.stringify(newLock)

fs.writeFileSync('yarn.lock', newLockString)