es6 Set的几种使用场景

// 数组去重 let arr = [1, 1, 2, 3]; let unique = [… new Set(arr)]; let a = new Set([1, 2, 3]); let b = new Set([4, 3, 2]); // 并集 let union = […new Set([…a, …b])]; // 交集 let intersect = […new Set([…a].filter(x => b.has(x)))]; // 差集 let difference = Array.from(new Set([…a].filter(x => !b.has(x))));