Singleton pattern implemented with Javascript.

Singleton.js

const printer = (function() {
  let printerInstance;
  
  function create() {
        
    function print() {
      console.log("Printing document...");  
    }
    function turnOn() {
      console.log("Turning on, checking for paper...");
    }
    
    return {
      print: print,
      turnOn: turnOn
    };    
  }
  
  return {
    getInstance: function() {
      if (!printerInstance) {
        printerInstance = create();
      }
      return printerInstance;
    }
  };
  
})();

const myPrinter = printer.getInstance();
myPrinter.turnOn();
myPrinter.print();