Set.prototype.has()
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
Set 实例的 has() 方法返回一个布尔值，指示该集合中是否存在具有指定值的元素。
¥The has() method of Set instances returns a boolean indicating whether an
element with the specified value exists in this set or not.
Try it
语法
参数
返回值
示例
使用 has() 方法
¥Using the has() method
js
const mySet = new Set();
mySet.add("foo");
console.log(mySet.has("foo")); // true
console.log(mySet.has("bar")); // false
const set1 = new Set();
const obj1 = { key1: 1 };
set1.add(obj1);
console.log(set1.has(obj1)); // true
console.log(set1.has({ key1: 1 })); // false, because they are different object references
console.log(set1.add({ key1: 1 })); // now set1 contains 2 entries
规范
| Specification |
|---|
| ECMAScript Language Specification # sec-set.prototype.has |
浏览器兼容性
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也可以看看
¥See also