es6 Set 操作数组

let a = new Set([1, 2, 3]);

let b = new Set([3, 5, 2]);

// 并集

let unionSet = new Set([...a, ...b]);//[1,2,3,5]

// 交集

let intersectionSet = new Set([...a].filter(x => b.has(x)));// [2,3]

// ab差集

let differenceABSet = new Set([...a].filter(x => !b.has(x)));