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WeakMap.prototype.has() - JavaScript | MDN
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  6. WeakMap.prototype.has()
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WeakMap.prototype.has()

Baseline Widely available

This feature is well established and works across many devices and browser versions. Its been available across browsers since julio de 2015.

El mtodo has() devuelve un boleano indicando ya sea, si el elemento con la llave especfica existe o no en el objeto WeakMap.

In this article

Prubalo

const weakmap1 = new WeakMap();
const object1 = {};
const object2 = {};

weakmap1.set(object1, "foo");

console.log(weakmap1.has(object1));
// Expected output: true

console.log(weakmap1.has(object2));
// Expected output: false

Sintaxis

wm.has(key);

Parmetros

identificador (key)

Requerido. La llave del elemento a comprobar en el objeto WeakMap.

Valor devuelto

Boolean

Devuelve true si el elemento con la llave especfica existe en el objeto WeakMap; de no encontrarse, devolver false.

Ejemplos

Utilizacin del mtodo has

js
var wm = new WeakMap();
wm.set(window, "foo");

wm.has(window); // Devuelve true
wm.has("baz"); // Devuelve false

Especificaciones

Specification
ECMAScript 2027 LanguageSpecification
# sec-weakmap.prototype.has

Compatibilidad con navegadores

Vea tambin

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  1. Objetos globales
  2. WeakMap
  3. Constructor
    1. WeakMap()
  4. Mtodos de instancia
    1. WeakMap.prototype.delete()
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    6. WeakMap.prototype.set()
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