typescript如何检测一个元素是否是某个枚举的值

enum AB {
  A="A",
  B="B"
}

console.log(Object.values(AB).includes("A" as AB))

其实它转换成原生JS如下：

var AB;
(function (AB) {
    AB["A"] = "A";
    AB["B"] = "B";
})(AB || (AB = {}));
console.log(Object.values(AB).includes("A"));