npm-babel-prep.js

//Initialize your project using npm init (in project folder) and create a directory called src
//Install babel dependencies by running
npm install babel-cli -D
npm install babel-preset-env -D
//Create a .babelrc file inside your project and add the following code inside it:
{
  "presets": ["env"]
}
//Add the following script to your scripts object in package.json:
"build": "babel src -d lib"
//Run npm run build whenever you want to transpile your code from your src to lib directories.