ECMAScript 6 sets: union, intersection, difference

index.js

// ECMAScript 6 sets: union, intersection, difference

// 1 union
let a = new Set([1,2,3]);
let b = new Set([4,3,2]);
let union = new Set([...a, ...b]); // {1,2,3,4}

// 2 intersection
let a = new Set([1,2,3]);
let b = new Set([4,3,2]);
let intersection = new Set([...a].filter(x => b.has(x))); // {2,3}

// 3 difference
let a = new Set([1,2,3]);
let b = new Set([4,3,2]);
let difference = new Set([...a].filter(x => !b.has(x))); // {1}