| CARVIEW |
Select Language
HTTP/2 200
content-type: text/html
x-guploader-uploadid: AAwnv3IQTbdKaKXJEOMShSC_v5h31xRlr5G5zpMZNsu4cS4pVDIau1r565Tbp_euPtPajw0x
cache-control: public, max-age=3600
expires: Sun, 12 Oct 2025 22:16:08 GMT
last-modified: Fri, 10 Oct 2025 01:07:13 GMT
etag: W/"e0f9275c1fec3b1a78d3ef9cc35adcad"
x-goog-generation: 1760058433711899
x-goog-metageneration: 1
x-goog-stored-content-encoding: identity
x-goog-stored-content-length: 141704
x-goog-meta-goog-reserved-file-mtime: 1760057086
x-goog-hash: crc32c=c4SS2A==, md5=4PknXB/sOxp40++cw1rcrQ==
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: d74fc2d15b7d9ab85418994e45a126bb
date: Sun, 12 Oct 2025 21:16:08 GMT
server: Google Frontend
via: 1.1 google
vary: Accept-Encoding
content-encoding: gzip
x-cache: miss
WeakRef.prototype.deref() - JavaScript | MDN
Toggle sidebar
WeakRef.prototype.deref()
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2021.
The deref() method of WeakRef instances returns this WeakRef's target value, or undefined if the target value has been garbage-collected.
Syntax
js
deref()
Parameters
None.
Return value
The target value of the WeakRef, which is either an object or a non-registered symbol. Returns undefined if the value has been garbage-collected.
Description
See the Notes on WeakRefs section of the WeakRef page for some important notes.
Examples
Using deref()
See the Examples
section of the WeakRef page for the complete example.
js
const tick = () => {
// Get the element from the weak reference, if it still exists
const element = this.ref.deref();
if (element) {
element.textContent = ++this.count;
} else {
// The element doesn't exist anymore
console.log("The element is gone.");
this.stop();
this.ref = null;
}
};
Specifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-weak-ref.prototype.deref |
Browser compatibility
Loading…