UMD Example

umd.common.js

(function (root, factory) { 
  if (typeof define === 'function' && define.amd) {
    define([], factory);    
  } else if (typeof module === 'object' && module.exports) {
    module.exports = factory();    
  } else { 
    root.returnExports = factory();  
  }
}(typeof self !== 'undefined' ? self : this, function () {

  // START OF YOUR CODE
  const helloWorld = () => {
    return "Hello World!"
  }
  return helloWorld;
  // END OF YOUR CODE
}));

umd.modern.js

((root, factory) => { 
  if (typeof define === 'function' && define.amd) {
    define([], factory);    
  } else if (typeof module === 'object' && module.exports) {
    module.exports = factory();    
  } else { 
    root.returnExports = factory();  
  }
})(typeof self !== 'undefined' ? self : this, () => {

  // START OF YOUR CODE
  const helloWorld = () => {
    return "Hello World!"
  }
  return helloWorld;
  // END OF YOUR CODE
});