webpack.config.js for CDK usage (small-scale projects)

cdk.webpack.config.js

const fs = require('fs')
const path = require('path')
const { BundleAnalyzerPlugin } = require('webpack-bundle-analyzer')

const DEFAULT_ANALYZER_PORT = 8888
const createBundleAnalyzerPlugin = (reportTitle, portOffset = 0) => new BundleAnalyzerPlugin({
  // Avoid CI crash issue
  analyzerMode: 'static',
  openAnalyzer: false,
  reportTitle,
  reportFilename: 'bundler_report.html',
  analyzerPort: DEFAULT_ANALYZER_PORT + portOffset,
})

const mapEntry = handlersPath => {
  const dirs = fs.readdirSync(handlersPath)
  // Get names of js files
  const names = dirs.filter(dir => {
    const isSubDir = !/(\.js|\.ts)$/.test(dir)
    if (isSubDir) {
      const subDir = fs.readdirSync(`${handlersPath}/${dir}`)
      // See if there is an index file for this sub directory
      return subDir.filter(n => /^index.js$/.test(n))
    }
    return /\.js$/.test(dir)
  })
  // Map entry object
  return names.reduce((obj, name) => {
    // Remove .js file extension
    const key = name.replace(/\.js$/, '')
    // Append 'index.js' if it is a directory
    const filePath = /\.js$/.test(name) ? name : `${name}/index.js`

    return {
      ...obj,
      [key]: `./${handlersPath}/${filePath}`,
    }
  }, {})
}

const createConfig = (handlersPath, name, index) => ({
  mode: 'development',
  target: 'node',
  entry: mapEntry(handlersPath),
  output: {
    path: `${process.cwd()}/${
      handlersPath
      // Replace '/build' with '/bundles' pathname
        .replace(/build/i, 'bundles')
      // Remove "/services"
        .replace(/\/services/i, '')
    }`,
    // Keep the bundle name same as the orignal function name
    filename: '[name].js',
    libraryTarget: 'umd',
  },
  node: {
    // Make sure that __dirname works in node env
    __dirname: true,
  },
  module: {
    rules: [
      /**
       * Use file loader to move chromnium .br files into /bin
       * @link https://github.com/alixaxel/chrome-aws-lambda/issues/80
       *
       * This is for correctly bundling the chromnium instance required by 'chrome-aws-lambda',
       * from the helper 'launchPuppeteerBrowserSession' of 'simply-utils'.
       */
      {
        test: /chrome\-aws\-lambda\/bin\/(.+)\.br$/,
        use: [{ loader: 'file-loader', options: { name: '/node_modules/chrome-aws-lambda/bin/[name].[ext]' } }],
      },
    ],
  },
  resolve: {
    alias: {
      src: path.resolve(__dirname, 'build'),
    },
  },
  externals: {
    // * Do NOT bundle 'aws-sdk' since it is included in the AWS Lambda NodeJS runtime
    'aws-sdk': 'aws-sdk',
  },
  // * Optional
  plugins: [createBundleAnalyzerPlugin(name, index)],
})

// Services directory path
const SERVICES_PATH = 'build/services'

// Create config for handlers folder of each service
module.exports = fs.readdirSync(SERVICES_PATH)
  .map((path, i) => createConfig(`${SERVICES_PATH}/${path}/handlers`, path, i))

/** Example output */
// Module.exports = [
//     CreateConfig('build/services/cron/handlers'),
//     CreateConfig('build/services/api/handlers'),
// ];
/** And they will be bundled into: */
// /bundles/cron/handlers
// /bundles/api/handlers