default string for class javascript code example

Example 1: javascript constructor default parameter

function greet(name, greeting, message = greeting + ' ' + name) {
  return [name, greeting, message]
}

greet('David', 'Hi')                     // ["David", "Hi", "Hi David"]
greet('David', 'Hi', 'Happy Birthday!')  // ["David", "Hi", "Happy Birthday!"]

Example 2: js unspecified parameters

function my_log(...args) {
     // args is an Array
     console.log(args);
     // You can pass this array as parameters to another function
     console.log(...args);
}