// Supply default values for parameters

// Before, using ES5...

function greetES5(message, to) {

}

greetES5('Good morning');

greetES5('Sup', 'CSS');

// After using ES2015/ES6...

// Define default parameter values in the function head

function greet(message, to = 'DOM') {

ChromeSamples.log(message + ', ' + to);

}

greet('Good morning');

greet('Sup', 'CSS');

// Another example

function f(x, y = 12) {

// y is 12 if not passed (or passed as undefined)

ChromeSamples.log(`${x} + ${y} = ${x + y}`);

}

f(3);

// Here, the default parameter won't be used since we're passing in a value, even though 0 is false-y.

f(7, 0);

// For more info, read: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Default_parameters#Passing_undefined

// Default arguments are evaluated at call time. This means

// a new array is created each time the function is called here:

function append(value, array = []) {

array.push(value);

ChromeSamples.log(array);

}

append(1);

append(2); // [2] instead of [1, 2]

// For more info, read: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Default_parameters#Evaluated_at_call_time