.babelrc

{
  "presets": ["env"],
  "plugins": ["external-helpers"]
}

full-setup.sh

mkdir -p src/lib && touch src/lib/index.js

# update (included) package.json
# include rollup.config.js & .babelrc files

# install dependencies
yarn add

# build command
npm run build

package.json

{
  "name": "WILL*DEFINITELY*NEED*A*NEW*NAME",
  "version": "0.0.1",
  "description": "IT DESERVES A GOOD DESCRIPTION",
  "main": "lib/bundle.js",
  "repository": "[email protected]:***super-awesome***",
  "author": "Derrick W <[email protected]> (I'll take the credit if don't want to update",
  "scripts": {
    "build": "./node_modules/.bin/rollup -c"
  },
  "license": "MIT",
  "license": "MIT",
  "dependencies": {},
  "devDependencies": {
    "eslint-plugin-import": "^2.2.0",
    "eslint-plugin-node": "^4.2.2",
    "rollup": "^0.41.6",
    "rollup-plugin-babel": "^2.7.1",
    "babel-cli": "^6.24.1",
    "babel-eslint": "^7.2.3",
    "babel-plugin-external-helpers": "^6.22.0",
    "babel-preset-env": "^1.4.0",
    "babel-preset-latest": "^6.24.1",
    "eslint": "^3.19.0",
    "eslint-config-standard": "^10.2.1",
    "eslint-plugin-promise": "^3.5.0",
    "eslint-plugin-standard": "^3.0.1",
    "istanbul": "^0.4.5",
    "jasmine": "^2.5.3",
    "proxyquire": "^1.7.11",
    "supertest": "^3.0.0"
  }
}

rollup.config.js

// rollup.config.js
export default {
  entry: 'src/lib/index.js',
  format: 'umd',
  dest: 'lib/bundle.js'
};