feds-cli/lib/development/ensureVendorDLLExists.js

CLI for Front-end Dev Stack

const webpack = require('webpack')
const pathExtName = require('path').extname
const pathResolve = require('path').resolve
const md5 = require('md5')
const fs = require('fs')
const globSync = require('glob').sync
const appRootPath = require('app-root-path').toString()
const vendorDLLPaths = require('../config/vendorDLLPaths')
const {createNotification} = require('../utils')

// -----------------------------------------------------------------------------
// PRIVATES

const importRegex = /(from '|require\(')([\w\-_]+)/g

const {dllName, dllOutputDir, dllJsonPath, dependenciesHashFilePath} = vendorDLLPaths

// We calculate a hash of the package.json's dependencies, which we can use
// to determine if dependencies have changed since the last time we built
// the vendor dll.
const currentDependenciesHash = md5(
  JSON.stringify(require(pathResolve(appRootPath, 'package.json')).dependencies)
)

function webpackConfigFactory (modules) {
  return {
    // We only use this for development, so lets always include source maps.
    devtool: 'inline-source-map',
    entry: {
      [dllName]: modules
    },
    output: {
      path: dllOutputDir,
      filename: `${dllName}.js`,
      library: dllName
    },
    plugins: [
      new webpack.DllPlugin({
        path: dllJsonPath,
        name: dllName
      })
    ]
  }
}

function getJsFilesFromSrcDir (srcPath) {
  return globSync(`${pathResolve(appRootPath, 'src', srcPath)}/**/*.js`)
}

function buildVendorDLL () {
  return new Promise((resolve, reject) => {
    Promise.all([
      Promise.resolve(getJsFilesFromSrcDir('client')),
      Promise.resolve(getJsFilesFromSrcDir('shared/universal'))
    ])
      .then(([clientFiles, universalFiles]) => {
        const isJsFile = file => pathExtName(file) === '.js'
        const allJSFiles = [...clientFiles, ...universalFiles].filter(isJsFile)
        const modules = allJSFiles.reduce((acc, cur) => {
          const fileContents = fs.readFileSync(cur, 'utf8')
          let match = importRegex.exec(fileContents)
          while (match != null) {
            acc.add(match[2])
            match = importRegex.exec(fileContents)
          }
          return acc
        }, new Set())

        createNotification({
          title: 'vendorDLL',
          level: 'info',
          message: 'Vendor DLL build complete. Check console for module list.'
        })
        console.log([...modules])

        const webpackConfig = webpackConfigFactory([...modules])
        const vendorDLLCompiler = webpack(webpackConfig)
        vendorDLLCompiler.run((err) => {
          if (err) {
            reject(err)
          }
          // Update the dependency hash
          if (!fs.existsSync(dllOutputDir)) {
            fs.mkdirSync(dllOutputDir)
          }
          fs.writeFileSync(dependenciesHashFilePath, currentDependenciesHash)

          resolve()
        })
      })
  })
}

// -----------------------------------------------------------------------------
// DEFAULT EXPORT

function ensureVendorDLLExists () {
  return new Promise((resolve, reject) => {
    if (!fs.existsSync(dependenciesHashFilePath)) {
      // builddll
      createNotification({
        title: 'vendorDLL',
        level: 'warn',
        message: 'Generating a new vendor dll for boosted development performance...'
      })
      buildVendorDLL().then(resolve).catch(reject)
    } else {
      // first check if the md5 hashes match
      const dependenciesHash = fs.readFileSync(dependenciesHashFilePath, 'utf8')
      const dependenciesChanged = dependenciesHash !== currentDependenciesHash

      if (dependenciesChanged) {
        createNotification({
          title: 'vendorDLL',
          level: 'warn',
          message: 'New vendor dependencies detected. Regenerating the vendor dll...'
        })
        buildVendorDLL().then(resolve).catch(reject)
      } else {
        createNotification({
          title: 'vendorDLL',
          level: 'info',
          message: 'No changes to existing vendor dependencies. Using the existing vendor dll.'
        })
        resolve()
      }
    }
  })
}

module.exports = ensureVendorDLLExists