How to merge two Sets in JavaScript

In this tutorial, we are going to learn about how to merge the two sets in JavaScript with the help of examples.

Merging means the joining of two or more sets into a single set.

Consider, we have the following two sets:

const a = new Set([1, 2, 3]);
const b = new Set([4, 5, 6]);

Now, we need to join above two sets like this:

{1, 2, 3, 4, 5, 6}

Using spread operator (…)

To merge the two sets into a single set, we can use the spread(…) operator in JavaScript.

The spread operator unpacks the iterables (such as sets, arrays, objects, etc) into a individual elements.

Here is an example:

const a = new Set([1, 2, 3]);
const b = new Set([4, 5, 6]);

const result = new Set([...a, ...b]);
console.log(result);

Output:

{1, 2, 3, 4, 5, 6}

We can also concatenate three sets in JavaScript like this:

const a = new Set([1, 2, 3]);
const b = new Set([4, 5, 6]);
const c = new Set([7, 8, 9]);


const result = new Set([...a, ...b, ...c]);
console.log(result);

Output:

{1, 2, 3, 4, 5, 6, 7, 8, 9}

We can also iterate over the each element in the set by using the for..of loop.

for (let element of result){
  console.log(element);
}