| CARVIEW |
Select Language
HTTP/2 200
content-type: text/html
x-guploader-uploadid: AAwnv3LXc2InIxyZB9s36N7bpN1XUG3p4v6uNqZ-4SXoNYKSsfK9xJuvMWxjIHrnU1V_C1eB
cache-control: public, max-age=3600
expires: Mon, 13 Oct 2025 02:15:56 GMT
last-modified: Fri, 10 Oct 2025 01:12:15 GMT
etag: W/"0f2db2302817486c9ea564c7b584bcf1"
x-goog-generation: 1760058735527755
x-goog-metageneration: 1
x-goog-stored-content-encoding: identity
x-goog-stored-content-length: 162151
x-goog-meta-goog-reserved-file-mtime: 1760057110
x-goog-hash: crc32c=V/iRTQ==, md5=Dy2yMCgXSGyepWTHtYS88Q==
x-goog-storage-class: STANDARD
accept-ranges: none
alt-svc: h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
alt-svc: clear
referrer-policy: strict-origin-when-cross-origin
x-content-type-options: nosniff
strict-transport-security: max-age=63072000
content-security-policy: default-src 'self'; script-src 'report-sample' 'self' 'wasm-unsafe-eval' https://www.google-analytics.com/analytics.js https://www.googletagmanager.com/gtag/js assets.codepen.io production-assets.codepen.io https://js.stripe.com 'sha256-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M=' 'sha256-YCNoU9DNiinACbd8n6UPyB/8vj0kXvhkOni9/06SuYw=' 'sha256-PZjP7OR6mBEtnvXIZfCZ5PuOlxoDF1LDZL8aj8c42rw='; script-src-elem 'report-sample' 'self' 'wasm-unsafe-eval' https://www.google-analytics.com/analytics.js https://www.googletagmanager.com/gtag/js assets.codepen.io production-assets.codepen.io https://js.stripe.com 'sha256-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M=' 'sha256-YCNoU9DNiinACbd8n6UPyB/8vj0kXvhkOni9/06SuYw=' 'sha256-PZjP7OR6mBEtnvXIZfCZ5PuOlxoDF1LDZL8aj8c42rw='; style-src 'report-sample' 'self' 'unsafe-inline'; object-src 'none'; base-uri 'self'; connect-src 'self' developer.allizom.org bcd.developer.allizom.org bcd.developer.mozilla.org updates.developer.allizom.org updates.developer.mozilla.org https://*.google-analytics.com https://*.analytics.google.com https://*.googletagmanager.com https://incoming.telemetry.mozilla.org https://observatory-api.mdn.allizom.net https://observatory-api.mdn.mozilla.net https://api.github.com/search/issues stats.g.doubleclick.net https://api.stripe.com; font-src 'self'; frame-src 'self' interactive-examples.mdn.mozilla.net interactive-examples.mdn.allizom.net mdn.github.io live-samples.mdn.mozilla.net live-samples.mdn.allizom.net *.mdnplay.dev *.mdnyalp.dev *.play.test.mdn.allizom.net https://v2.scrimba.com https://scrimba.com jsfiddle.net www.youtube-nocookie.com codepen.io survey.alchemer.com https://js.stripe.com; img-src 'self' data: *.githubusercontent.com *.googleusercontent.com *.gravatar.com mozillausercontent.com firefoxusercontent.com profile.stage.mozaws.net profile.accounts.firefox.com developer.mozilla.org mdn.dev interactive-examples.mdn.mozilla.net interactive-examples.mdn.allizom.net wikipedia.org upload.wikimedia.org https://mdn.github.io/shared-assets/ https://mdn.dev/ https://*.google-analytics.com https://*.googletagmanager.com www.gstatic.com; manifest-src 'self'; media-src 'self' archive.org videos.cdn.mozilla.net https://mdn.github.io/shared-assets/; child-src 'self'; worker-src 'self';
x-frame-options: DENY
origin-trial: AxVILwizhbMjxFeHOn1P3R8niO1RJY/smaK4B4d1rLzc1gTaxtXMSaTi+FoigYgCw40uFRDwFcEAeqDR+vVLOW4AAABfeyJvcmlnaW4iOiJodHRwczovL2RldmVsb3Blci5tb3ppbGxhLm9yZyIsImZlYXR1cmUiOiJQcml2YXRlQXR0cmlidXRpb25WMiIsImV4cGlyeSI6MTc0MjA3OTYwMH0=
x-cloud-trace-context: 5396efff005e58d6fdcd7f708943c3c0
date: Mon, 13 Oct 2025 01:15:56 GMT
server: Google Frontend
via: 1.1 google
vary: Accept-Encoding
content-encoding: gzip
x-cache: miss
WeakMap.prototype.delete() - JavaScript | MDN
Toggle sidebar
このページはコミュニティーの尽力で英語から翻訳されました。MDN Web Docs コミュニティーについてもっと知り、仲間になるにはこちらから。
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 |
ブラウザーの互換性
Loading…