Example of the module pattern

module-pattern.js

function createSecret() {
  //private variable
  let secretNum = Math.round(Math.random() * 10);

  //public function
  let guessSecret = function(guess) {
    return guess === secretNum ? 'Correct' : 'Try again';
  }

  return guessSecret;
}

let lottery1 = createSecret();
console.log(lottery1(5));

let lottery2 = createSecret();
console.log(lottery2(5));