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WeakMap.prototype.delete() - JavaScript | MDN
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WeakMap.prototype.delete()
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since 2015年7月.
delete() メソッドは、 WeakMap オブジェクトから指定された要素を削除します。
試してみましょう
const weakmap1 = new WeakMap();
const object1 = {};
weakmap1.set(object1, 42);
console.log(weakmap1.delete(object1));
// Expected output: true
console.log(weakmap1.has(object1));
// Expected output: false
構文
wm.delete(key);
引数
key-
WeakMapオブジェクトから削除する要素のキーです。
返値
WeakMap オブジェクト内の要素を削除するのに成功した場合、true を返します。WeakMap 内でキーが見つからなかったり、キーがオブジェクトでなかったりした場合、false を返します。
例
delete() メソッドの使用
js
var wm = new WeakMap();
wm.set(window, "foo");
wm.delete(window); // true を返す。削除に成功。
wm.has(window); // false を返す。 window はもう WeakMap に存在しない。
仕様書
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-weakmap.prototype.delete |
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