javascript parameter default value 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: javascript default parameters

function multiply(a, b = 1) {
  return a * b;
}

Example 3: js default parameter

function read_file(file, default_param = false) {
  // Code
}

Example 4: js default parameter

function greeting (name = 'stranger') {
  console.log(`Hello, ${name}!`)
}

greeting('Nick') // Output: Hello, Nick!
greeting() // Output: Hello, stranger!

Example 5: default value of functin atribute

function say(message='Hi', number=7) {
    console.log(message);
  	console.log(number);
}

say();
// 'Hi'
// 7