JavaScript union (a ∪ b): create a set that contains the elements of both sets a and set b. To get a union of two Sets, use the spread syntax (…) to unpack the values of the Sets into an array and pass the result to the Set() constructor.
new Set([...set1, ...set2])The new Set will contain the union of the other two.
JavaScript Set union
Simple example code.
<!DOCTYPE html>
<html>
<body>
<script>
let a = new Set([10,20,30]);
let b = new Set([40,30,20]);
let union = new Set([...a, ...b]);
console.log(union)
</script>
</body>
</html>Output:
We used the spread syntax (…) to unpack the values from the two Set objects into an array.
const set1 = new Set(['a', 'b', 'c']);
const set2 = new Set(['a', 'b', 'd']);
const arr = [...set1, ...set2];
console.log(arr); // 👉️ ['a', 'b', 'c' ,'a', 'b', 'd']Get a Union of Two Sets using for-of loop
function getUnion(setA, setB) {
const union = new Set(setA);
for (const element of setB) {
union.add(element);
}
return union;
}
const set1 = new Set(['a', 'b', 'c']);
const set2 = new Set(['a', 'b', 'd']);
console.log(getUnion(set1, set2)); // 👉️ {'a', 'b', 'c', 'd'}
Do comment if you have any doubts or suggestions on this JS set topic.
Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.
OS: Windows 10
Code: HTML 5 Version