摘要：
<!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <title>Page Title</title> <meta name="vie 阅读全文
摘要：
const setA = new Set([1, 2, 4, 5]) const setB = new Set([5,4, 3]) // 并集 res = new Set([...setA, ...setB]) // 交集 res = new Set([...setA].filter( item = 阅读全文