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Showing content from https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/Map/clear below:

Map.prototype.clear() - JavaScript | MDN

Map.prototype.clear()

Baseline Widely available

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 参数

无。

返回值

无(undefined)。

示例 使用 clear()
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
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