JavaScript has a number of built-in object types, such as:

Math, Date, Object, Function, Boolean, Symbol, Array, Map, Set, Promise, JSON, etc.

We call these objects native objects.

Constructors are special functions that allow us to build instances of the above built-in native objects.

In order to use a constructor, we need to prepend it with the operator new.

Let us create a new instance of Date object. We should run new Date() ,.After running, we will get the following result.

Fri Feb 03 2022 20:06:21 GMT+0530

One thing to note - not all the built-in objects come with a constructor function. Ex. the Math object

When we try to run new Math(), we get an Uncaught TypeError, stating that Math is not a constructror.

Let us take an example.

function Icecream(flavor) { this.flavor = flavor; this.meltIt = function() { console.log(`The ${this.flavor} icecream has melted`); } }

now, from the above code, one can build as many IceCream as they want.

let chocoIcecream = new Icecream("choco");
let vanillaIcecream = new Icecream("vanilla");
chocoIcecream; // --> Icecream {flavor: 'choco', meltIt: ƒ}
vanillaIcecream; // --> Icecream {flavor: 'vanilla', meltIt: ƒ}

In the code aboev, we just built 2 instance objects of IceCream() type.

The most common use case of new is to use it with one of the built-in object types.