JavaScript Interview Questions

ES6, also known as ECMAScript 2015, introduced several new features to JavaScript that enhanced its capabilities and improved developer productivity. Some of the notable features include:

• Arrow Functions: Provide a concise syntax for writing functions.
• Classes: Offer a more straightforward and clearer syntax to create objects and deal with inheritance.
• Template Literals: Allow embedding expressions in strings and support multi-line strings.
• Default Parameters: Enable setting default values for function parameters.
• Destructuring Assignment: Allows unpacking values from arrays or properties from objects into distinct variables.
• Spread Operator: Expands elements of an array or object.
• let and const Declarations: Provide block-scoped variables.

Here are some examples of these features:

// Arrow Function
const add = (a, b) => a + b;
console.log(add(2, 3)); // 5

// Class
class Person {
    constructor(name) {
        this.name = name;
    }
    greet() {
        console.log(`Hello, ${this.name}`);
    }
}
const john = new Person('John');
john.greet(); // Hello, John

// Template Literal
const greeting = `Hello,
World!`;
console.log(greeting);

// Default Parameter
function multiply(a, b = 2) {
    return a * b;
}
console.log(multiply(3)); // 6

// Destructuring Assignment
const [x, y] = [1, 2];
console.log(x, y); // 1 2

// Spread Operator
const arr1 = [1, 2];
const arr2 = [...arr1, 3, 4];
console.log(arr2); // [1, 2, 3, 4]

// let and const
let a = 10;
const b = 20;
console.log(a, b); // 10 20