JavaScript Interview Question #107

What does the new operator do in JavaScript?

Closures, Prototypes, Classes & Advanced Functions Mid-Level Intermediate

Quick Interview Answer

When used with a constructable function or class, new creates a new object, links it to the constructor's prototype, calls the constructor with this bound to the new object, and normally returns that object.

Detailed Explanation

If a constructor explicitly returns another non-primitive object, that object can become the result instead. Modern code often uses class syntax, but understanding new is important because classes are built on JavaScript's prototype model.

Code Example

function Product(name, price) {
    this.name = name;
    this.price = price;
}

Product.prototype.describe = function () {
    return `${this.name}: $${this.price}`;
};

const product = new Product("Keyboard", 50);
console.log(product.describe());