ES6 Default Parameters

Funtions accept default parameters and destructuring parameters.

function addToFive(addTo = 0) {
	return addTo + 5;
}
const ex1 = addToFive();
const ex2 = addToFive(5);
console.log(ex1, ex2); // 5, 10

function fullname ({firstname, lastname}) {
	return `${firstname} ${lastname}`;
}
const user = { firstname: 'Theodore', lastname: 'Logan', age: '20' };
const fullname = fullname(user);
console.log(`Hello ${fullname}`); //Hello Theodore Logan

When destructuring you can also assign defaults.

function myFunc({age = 42}) {
	console.log(age); 
};
myFunc({name: 'Theodore'}); //42
myFunc({name: 'Theodore', age: 30}); //30