function greet(greeting, name="Anonymous"){console.log(greeting +", "+ name);}greet(); // undefined, Anonymousgreet('Hello'); // Hello, Anonymousgreet('Hello', 'Dady'); // Hello, Dady
// ES5function greet(cb){cb();}greet(function(){console.log("completed"); // completed})// ES6function greet(() => console.log("completed")){cb();}greet();