Set.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.

clear() 方法會從一個 Set 物件中移除其所有元素。

嘗試一下

const set1 = new Set();
set1.add(1);
set1.add("foo");

console.log(set1.size);
// Expected output: 2

set1.clear();

console.log(set1.size);
// Expected output: 0

語法

js
mySet.clear();

回傳值

undefined。

範例

使用 clear 方法

js
var mySet = new Set();
mySet.add(1);
mySet.add("foo");

mySet.size; // 2
mySet.has("foo"); // true

mySet.clear();

mySet.size; // 0
mySet.has("bar"); // false

規範

Specification
ECMAScript® 2026 Language Specification
# sec-set.prototype.clear

瀏覽器相容性

參見