Các tính năng mới trong ES6+

Destructuring

// Array destructuring
let numbers = [1, 2, 3];
let [first, second, third] = numbers;
console.log(first, second, third); // 1 2 3

// Object destructuring
let person = { name: "John", age: 30, city: "New York" };
let { name, age } = person;
console.log(name, age); // John 30

// Destructuring trong tham số hàm
function printPerson({ name, age }) {
  console.log(`${name} is ${age} years old`);
}

Spread và Rest Operators

// Spread với mảng
let arr1 = [1, 2, 3];
let arr2 = [4, 5, 6];
let combined = [...arr1, ...arr2];
console.log(combined); // [1, 2, 3, 4, 5, 6]

// Spread với object
let obj1 = { a: 1, b: 2 };
let obj2 = { c: 3, d: 4 };
let merged = { ...obj1, ...obj2 };
console.log(merged); // { a: 1, b: 2, c: 3, d: 4 }

// Rest parameters
function sum(...numbers) {
  return numbers.reduce((total, num) => total + num, 0);
}
console.log(sum(1, 2, 3, 4, 5)); // 15

Template Literals

let name = "John";
let age = 30;

// String interpolation
let message = `Hello, my name is ${name} and I'm ${age} years old.`;
console.log(message);

// Multi-line strings
let multiLine = `
  This is a
  multi-line
  string
`;

Default Parameters

function greet(name = "Guest", greeting = "Hello") {
  console.log(`${greeting}, ${name}!`);
}

greet(); // "Hello, Guest!"
greet("John"); // "Hello, John!"
greet("Jane", "Hi"); // "Hi, Jane!"

Optional Chaining và Nullish Coalescing

let user = {
  profile: {
    name: "John",
    address: {
      city: "New York"
    }
  }
};

// Optional chaining
let city = user?.profile?.address?.city;
console.log(city); // "New York"

let invalidCity = user?.profile?.invalid?.city;
console.log(invalidCity); // undefined

// Nullish coalescing
let defaultValue = user?.invalidProp ?? "Default Value";
console.log(defaultValue); // "Default Value"