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Set.prototype.union() - JavaScript | MDN
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Set.prototype.union()

Baseline 2024
Newly available

Since 2024 6, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.

Set union() .

In this article

js
union(other)

other

Set

other Set .

(union) .

AB={xxA or xB}A\cup B = {x\midx\in A\text{ or }x\in B}

.

. A B . [ . A B .]

union() other . this this Set . keys() other this other .

this , other .

union()

(<10) (<10) . .

js
const evens = new Set([2, 4, 6, 8]);
const squares = new Set([1, 4, 9]);
console.log(evens.union(squares)); // Set(6) { 2, 4, 6, 8, 1, 9 }

Specification
ECMAScript 2027 LanguageSpecification
# sec-set.prototype.union

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  2. Set
    1. Set()
    1. Set[Symbol.species]
    1. Set.prototype.add()
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    4. Set.prototype.difference()
    5. Set.prototype.entries()
    6. Set.prototype.forEach()
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    8. Set.prototype.intersection()
    9. Set.prototype.isDisjointFrom()
    10. Set.prototype.isSubsetOf()
    11. Set.prototype.isSupersetOf()
    12. Set.prototype.keys()
    13. Set.prototype.symmetricDifference()
    14. Set.prototype.union()
    15. Set.prototype.values()
    16. Set.prototype[@@iterator]()
    1. Set.prototype.size
  8. Object/Function
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