Map.prototype.clear()
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.
Map 实例的 clear() 方法会移除该 map 中的所有元素。
尝试一下
const map1 = new Map();
map1.set("bar", "baz");
map1.set(1, "foo");
console.log(map1.size);
// Expected output: 2
map1.clear();
console.log(map1.size);
// Expected output: 0
语法
js
clear()
参数
无。
返回值
无（undefined）。
示例
使用 clear()
js
const myMap = new Map();
myMap.set("bar", "baz");
myMap.set(1, "foo");
console.log(myMap.size); // 2
console.log(myMap.has("bar")); // true
myMap.clear();
console.log(myMap.size); // 0
console.log(myMap.has("bar")); // false
规范
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-map.prototype.clear |