What new features are you familiar with in ES6…

let, const, var: use let and const for block scope, var for function scope. const for constants, let for variables that can be reassigned.
Arrow Functions: shorthand syntax for declaring functions. Lexical this.

Template Literals: allow embedding expressions and multiline strings.

const name = "World";
const greeting = `Hello, ${name}!`; // "Hello, World!"

Destructuring Assignment: convenient way to extract values from arrays and objects.

const person = { firstName: "John", lastName: "Doe" };
const { firstName, lastName } = person; // firstName = "John", lastName = "Doe"

Spread operator (...) and Rest parameters (...): Spread for expanding and merging arrays/objects. Rest for collecting remaining function arguments into an array.

const arr1 = [1, 2];
const arr2 = [...arr1, 3, 4]; // [1, 2, 3, 4]

function sum(...numbers) {
  return numbers.reduce((acc, current) => acc + current, 0);
}
sum(1, 2, 3); // 6

Classes: syntactic sugar over prototypal inheritance.

class Car {
  constructor(brand) {
    this.brand = brand;
  }
  drive() {
    console.log(`${this.brand} is driving.`);
  }
}

Modules: tool for organizing code using import and export.

// module.js
export const PI = 3.14;

// main.js
import { PI } from './module.js';

Promises: simplify working with asynchronous code.

new Promise((resolve, reject) => {
  // Asynchronous operation
  if (success) {
    resolve("Success!");
  } else {
    reject("Error!");
  }
})
.then(result => console.log(result))
.catch(error => console.error(error));

for...of loop: iterate over iterable objects (arrays, strings, Map, Set, etc.).

const arr = [1, 2, 3];
for (const value of arr) {
  console.log(value); // 1, 2, 3
}

Set and Map: new data structures. Set for unique values, Map for key-value pairs.

What new features are you familiar with in ES6?