DefaultParameters.js

// ES5
function myFunctionES5(name, location, food) {
  var myName = name || "Default Name";
  var myLocation = location || "New York";
  var myFood = food || "Pizza plz";
  console.log({
    name:myName,
    location:myLocation,
    food:myFood
  })
}

// ES6
function myFunctionES6(name="Default Name", location="New York", food="Pizza Plz") {
  console.log({name, location, food});
}

myFunctionES5();
// prints { name: 'Default Name', location: 'New York', food: 'Pizza plz' }
myFunctionES6();
// prints { name: 'Default Name', location: 'New York', food: 'Pizza plz' }

myFunctionES5(null, "Vietnam", "Pho");
// prints { name: 'Default Name', location: 'Vietnam', food: 'Pho' }
myFunctionES6(null, "Vietnam", "Pho");
// prints { name: null, location: 'Vietnam', food: 'Pho' }