拷贝数组中合集

• 计算合集

  const dayCount = [0,1,2,3];
  const weekCount = [0,1,2] 
  // 计算天数集合、星期集合的交集
      const dayArr = new Set(dayCount);
      const weekArr = new Set(weekCount);
      const sameArr = Array.from(
        new Set([...dayArr].filter(x => weekArr.has(x)))
      );
  console.log(sameArr) // [0,1,2]