JavaScript Set() Constructor
Last Updated :
23 Jul, 2025
The Javascript Set constructor is used to create Set objects. It will create a set of unique values of any type, whether primitive values or object preferences. It returns the new Set object. It mainly helps in creating a new set of objects which contains unique elements.
Syntax:
new Set()
new Set(iterable)
Parameters:
This method accepts a single parameter that is described below:
- iterable: If an object is passed, all values will be added to the new set. If the parameter is not specified then the new set is empty.
Return Value:
- This method returns a new Set object.
Example 1: In this example, we will see how to create a new Set object.
JavaScript
const mySet = new Set();
mySet.add("California");
mySet.add("India");
mySet.add("Russia");
mySet.add(10);
const myObject = { a: 1, b: 8 };
mySet.add(myObject);
console.log(mySet);
Output:
Set(5) { 'California', 'India', 'Russia', 10, { a: 1, b: 8 } }
Example 2: In this example, we will see that set takes only a unique value.
JavaScript
const mySet = new Set();
mySet.add("California");
mySet.add("India");
mySet.add("California");
mySet.add(10);
mySet.add(10);
const myObject = { a: 1, a: 5 };
mySet.add(myObject);
console.log(mySet);
Output:
Set(4) { 'California', 'India', 10, { a: 5 } }
In this example, we have added two times "California" and 10 but it creates a set with unique values.
We have a complete list of Javascript Set methods, to check those please go through this Sets in JavaScript article.
Supported Browsers:
- Chrome
- Edge
- Firefox
- Opera
- Safari
Explore
JavaScript Basics
Array & String
Function & Object
OOP
Asynchronous JavaScript
Exception Handling
DOM
Advanced Topics