Widely availableSupported across all major browsers. Safe to use in production.
WeakMap and WeakSet Widely available

WeakSet

A WeakSet object stores unique values of any type without creating strong references to the values, such that membership in the set does not prevent garbage collection of the value.

WeakMap and WeakSet

Overview

A WeakSet object stores unique values of any type without creating strong references to the values, such that membership in the set does not prevent garbage collection of the value.

Browser support

Feature Desktop Mobile
Chrome
Edge
Firefox
Safari
Chrome Android
Safari iOS
WeakSet
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WeakSet.WeakSet

The WeakSet() constructor creates WeakSet objects.
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WeakSet.WeakSet.iterable allowed

`new WeakSet(iterable)`
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WeakSet.WeakSet.null allowed

`new WeakSet(null)`
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WeakSet.add

The add() method of WeakSet instances inserts the specified value into this set, if it is not already present.
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WeakSet.delete

The delete() method of WeakSet instances removes the specified value from this set, if it is in the set.
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WeakSet.has

The has() method of WeakSet instances returns a boolean indicating whether the specified value exists in this WeakSet or not.
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WeakSet.symbol as keys

Non-registered symbols as keys
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1+Supported (version) Not supported ※Has note Sub-feature descriptions sourced from MDN Web Docs (CC BY-SA 2.5)

Syntax

JAVASCRIPT 
const processed = new WeakSet();

function handle(obj) {
  if (processed.has(obj)) return; // Already processed
  processed.add(obj);
  // Execute processing
}

Live demo

Track processed objects

onedegreeprocessingobject WeakSet to, doubleprocessing prevention..

PreviewFullscreen

Check object membership

specific. Object to include or, reference in manage..

PreviewFullscreen

Simulate circular-reference detection

re processing to, in to object recordnoneloop preventsimul-tion..

PreviewFullscreen

Use cases

  • Using WeakSet

    A WeakSet object stores unique values of any type without creating strong references to the values, such that membership in the set does not prevent garbage collection of the value.

Cautions

  • No specific concerns. Stable across all major browsers.

Accessibility

  • When updating the DOM dynamically, announce important changes to assistive technology with aria-live regions.

Related links

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