npm-it.js

const path = require('path')
const { promisify } = require('util')
const fs = require('fs')

function getApps() {
  return promisify(fs.readdir)('app')
}

const defaultManifest = {
  bower: [],
  vendor: []
}

const componentsString = 'components/'

function fixStylePaths(stylePath) {
  if (stylePath.startsWith('../../bower')) {
    const newStylePath = stylePath.substring(
      stylePath.indexOf(componentsString) + componentsString.length
    )
    return `../node_modules/${newStylePath}`
  }

  return stylePath
}

function buildNewManifestJson(name) {
  const manifestJson = require(path.resolve('app', name, 'manifest.json'))
  const newVendorPaths = Array.from(
    new Set([
      ...manifestJson.bower.map(packagePath => `../node_modules/${packagePath}`),
      ...manifestJson.vendor
    ])
  )

  return Object.assign({}, defaultManifest, {
    vendor: newVendorPaths,
    styles: manifestJson.styles ? manifestJson.styles.map(fixStylePaths) : []
  })
}

async function buildNewPackageJson(appName) {
  const { dependencies, devDependencies, name, version } = require(path.resolve(
    'app',
    appName,
    'bower.json'
  ))

  if (await promisify(fs.exists)(path.resolve('app', appName, 'package.json'))) {
    const packageJson = require(path.resolve('app', appName, 'package.json'))

    return Object.assign({}, { dependencies, devDependencies, name, version }, packageJson)
  } else {
    return { dependencies, devDependencies, name, version }
  }
}

async function convertAppsToNpm() {
  const apps = (await getApps()).filter(name => !name.startsWith('.'))
  const appsWithContent = await Promise.all(
    apps.map(async name => {
      const content = await promisify(fs.readdir)(path.resolve('app', name))
      return {
        name,
        content
      }
    })
  )

  const bowerApps = appsWithContent.filter(app => app.content.includes('bower.json'))

  bowerApps.map(async ({ name }) => {
    const newPackageJson = await buildNewPackageJson(name)
    const newManifestJson = buildNewManifestJson(name)

    await Promise.all([
      promisify(fs.writeFile)(path.resolve('app', name, 'manifest.json'), JSON.stringify(newManifestJson, null, 2) + '\n'),
      promisify(fs.writeFile)(path.resolve('app', name, 'package.json'), JSON.stringify(newPackageJson, null, 2) + '\n')
    ])

    console.log(`Finished transitioning ${name} from bower to npm`)
    await promisify(fs.unlink)(path.resolve('app', name, 'bower.json'))
    console.log(`Removed bower.json from ${name}`)

  })
}

convertAppsToNpm()