type Person = {

  name?: string,

  age?: number,

  isActive?: boolean

};

​

const defaultPerson: Person = {

  name: "John Doe",

  age: 25,

  isActive: true

};

​

function getPersonDetails(person: Person = defaultPerson) {

  // Function logic here

}

​

// Usage

const person1: Person = {

  name: "Alice",

  isActive: false

};

getPersonDetails(person1); // Person object with default values for missing properties will be assigned

​

const person2: Person = {};

getPersonDetails(person2); // Person object with default values for all properties will be assigned

function sayName({ first, last = 'Smith' }: {first: string; last?: string }): void {

  const name = first + ' ' + last;

  console.log(name);

}

​

sayName({ first: 'Bob' });

function greet(name: string = "Guest") {

  console.log(`Hello, ${name}!`);

}

​

// Calling the function without providing an argument for 'name'

greet(); // Output: "Hello, Guest!"

​

// Calling the function with an argument for 'name'

greet("John"); // Output: "Hello, John!"