How to merge Sets using JavaScript

Merge Set Objects using JavaScript #

To merge Sets, use the spread operator (...) to unpack the values of two or more Sets into an array and pass them into the Set() constructor, e.g. new Set([...set1, ...set2]). The new Set will contain all of the elements from the provided Set objects.

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const set1 = new Set(['one', 'two']);
const set2 = new Set(['three']);

const set3 = new Set([...set1, ...set2]);
console.log(set3); // 👉️ {'one', 'two', 'three'}

We used the spread operator (...) to unpack the elements from 2 Set objects into an array.

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const set1 = new Set(['one', 'two']);

console.log([...set1]); // 👉️ ['one', 'two']

The last step is to pass the array to the Set() constructor, which takes an iterable as a parameter.

With the values in place, the example looks like:

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const set3 = new Set(['one', 'two', 'three']);

This process could be repeated with as many Set objects as necessary.

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const set1 = new Set(['one']);
const set2 = new Set(['two']);
const set3 = new Set(['three']);

const set4 = new Set([...set1, ...set2, ...set3]);
console.log(set4); // 👉️ {'one', 'two', 'three'}

Further Reading #

• How to Remove an Element from a Set using JavaScript
• How to merge Maps using JavaScript