WeakSet.prototype.has()

The has() method returns a boolean indicating whether an object exists in a WeakSet or not.

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Syntax

has(value)

Parameters

value: Required. The object to test for presence in the WeakSet.

Return value

Boolean: Returns true if an element with the specified value exists in the WeakSet object; otherwise false.

Examples

Using the `has()` method

const ws = new WeakSet();
const obj = {};
ws.add(window);

ws.has(window);  // returns true
ws.has(obj);     // returns false

Specifications

Specification
ECMAScript Language Specification # sec-weakset.prototype.has

Browser compatibility

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See also