javascript_sets.js

// create some sets
let setA = new Set([1, 2, 3, 4]);
let setB = new Set([3, 4, 5, 6]);
let setC = new Set([5, 6, 7, 8]);

// create a new set with the union of setA, setB, and setC
let unionSet = new Set([...setA, ...setB, ...setC]);
console.log(unionSet); // Set {1, 2, 3, 4, 5, 6, 7, 8}

// create a new set with the intersection of setA, setB, and setC
let intersectionSet = new Set([...setA].filter(x => setB.has(x) && setC.has(x)));
console.log(intersectionSet); // Set {5, 6}