configure babel to support ESM and async/await (SO #53540716)

README.md

$ tree
.
├── README.md
├── babel.config.js
├── lib
├── package.json
└── src
    ├── app.js
    └── lib.js

2 directories, 5 files

$ npm install

$ npm run build

$ tree -I node_modules
.
├── README.md
├── babel.config.js
├── lib
│   ├── app.js
│   └── lib.js
├── package-lock.json
├── package.json
└── src
    ├── app.js
    └── lib.js

references

• original SO question
• @babel/preset-env
• @babel/plugin-transform-async-to-generator

app.js

// src/app.js

import { guid, currentDateTimeISOString, stringToBoolean } from './lib'

async function hello() {
  return 'world'
}

babel.config.js

module.exports = {
  plugins: ['@babel/plugin-transform-async-to-generator'],
  presets: [
    [
      '@babel/env',
      {
        targets: {
          node: 'current'
        },
        modules: 'cjs'
      }
    ]
  ]
}

lib.js

// src/lib.js

// generate unique id
export const guid = () => {
  const s4 = () => {
    return Math.floor((1 + Math.random()) * 0x10000)
      .toString(16)
      .substring(1)
  }
  return (
    s4() +
    s4() +
    '-' +
    s4() +
    '-' +
    s4() +
    '-' +
    s4() +
    '-' +
    s4() +
    s4() +
    s4()
  )
}

// get current date as ISO string
export const currentDateTimeISOString = () => {
  var iso_string = new Date().toISOString()
  return iso_string
}

// convert boolean string to boolean
export const stringToBoolean = val => {
  var a = {
    true: true,
    false: false
  }
  return a[val]
}

package.json

{
  "name": "babel-esm-async",
  "version": "0.0.0",
  "main": "lib/app.js",
  "scripts": {
    "build": "babel src -d lib"
  },
  "devDependencies": {
    "@babel/cli": "^7.2.0",
    "@babel/core": "^7.2.0",
    "@babel/plugin-transform-async-to-generator": "^7.2.0",
    "@babel/preset-env": "^7.2.0"
  }
}