WeakMap.prototype.has()
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
O método has()
retorna um booleano indicando se um elemento com a chave especificada existe no objeto WeakMap
ou não.
Experimente
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
Sintaxe
wm.has(chave);
Parameters
- chave
-
Obrigatório. A chave do elemento cuja presença deve ser verificada no objeto
WeakMap
.
Valor de retorno
- Boolean
-
Retorna
true
se um elemento com a chave especificada existir no objetoWeakMap
. Caso contrário, retornafalse
.
Exemplos
Utilizando o método has
js
var wm = new WeakMap();
wm.set(window, "foo");
wm.has(window); // retorna true
wm.has("baz"); // retorna false
Especificações
Specification |
---|
ECMAScript® 2025 Language Specification # sec-weakmap.prototype.has |
Compatibilidade com navegadores
Report problems with this compatibility data on GitHubdesktop | mobile | server | ||||||||||||
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has |
Legend
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- Full support
- Full support
- See implementation notes.
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