What is ES6?

ES6 (ECMAScript 2015) massively upgraded JavaScript. It added cleaner syntax, new concepts, and made JavaScript more powerful and readable.

1. let and const

Better variable declarations.

let x = 10;
const y = 20;
      

2. Arrow Functions

const add = (a, b) => a + b;
console.log(add(5, 3));
      

3. Template Literals

const name = "Kaloyan";
console.log(`Hello, ${name}!`);
      

4. Default Parameters

function greet(name = "Guest") {
  console.log("Hello " + name);
}
      

5. Spread Operator (...)

const nums = [1, 2, 3];
const more = [...nums, 4, 5];
      

6. Rest Parameters

function sum(...values) {
  return values.reduce((a, b) => a + b);
}
      

7. Destructuring

const person = { name: "Kaloyan", age: 12 };
const { name, age } = person;
      

8. Classes

class Car {
  constructor(model) {
    this.model = model;
  }
}

const c = new Car("Subaru");
      

9. Promises

const delay = ms => new Promise(res => setTimeout(res, ms));

delay(1000).then(() => console.log("Done!"));
      

10. Modules (import/export)

// export
export const pi = 3.14;

// import
import { pi } from "./math.js";
      

What's Next?

You now know the most important ES6 features — next you’ll use them inside real modern JavaScript workflows and APIs.