要获得交集，您可以迭代集合中的项目并检查它们是否属于到另一个：

To get the intersection, you can iterate the items of a set and check if they belong to the other one:

var intersect = new Set();
for(var x of mySet1) if(mySet2.has(x)) intersect.add(x);

在ES7中，您可以使用 array comprehensions 或 generator comprehensions ：

In ES7 you can simplify it with array comprehensions or generator comprehensions:

var intersect = new Set((for (x of mySet1) if (mySet2.has(x)) x));