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Map.prototype.has() - JavaScript | MDN
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Map.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() de las instancias Map regresa un booleano indicando si un elemento con la llave especificada existe o no en este map.

In this article

Prubalo

const map1 = new Map();
map1.set("bar", "foo");

console.log(map1.has("bar"));
// Expected output: true

console.log(map1.has("baz"));
// Expected output: false

Sintaxis

js
has(key)

Parmetros

key

La llave del elemento que se quiere comprobar si existe en el objeto Map.

Valor devuelto

true si un elemento con la llave especificada existe en el objeto Map; de lo contrario regresa false.

Ejemplos

Usando has()

js
const myMap = new Map();
myMap.set("bar", "foo");

console.log(myMap.has("bar")); // true
console.log(myMap.has("baz")); // false

Especificaciones

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

Compatibilidad con navegadores

Vase tambin

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This page was last modified on 11 feb 2025 by MDN contributors.

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  1. Objetos globales
  2. Map
  3. Constructor
    1. Map() constructor
  4. Mtodos estticos
    1. Map.groupBy()
  5. Propiedades estticas
    1. Map[Symbol.species]
  6. Mtodos de instancia
    1. Map.prototype.clear()
    2. Map.prototype.delete()
    3. Map.prototype.entries()
    4. Map.prototype.forEach()
    5. Map.prototype.get()
    6. getOrInsert()
    7. getOrInsertComputed()
    8. Map.prototype.has()
    9. Map.prototype.keys()
    10. Map.prototype.set()
    11. Map.prototype.values()
    12. Map.prototype[Symbol.iterator]()
  7. Propiedades de instancia
    1. Map.prototype.size
  8. Herencia
  9. Object/Function
  10. Mtodos estticos
    1. Function.prototype.apply()
    2. Function.prototype.bind()
    3. Function.prototype.call()
    4. Function.prototype.toString()
    5. [Symbol.hasInstance]()
  11. Propiedades estticas
    1. Function.displayName
    2. Function.length
    3. Function.name
    4. prototype
    5. Function.prototype.arguments
    6. Function.caller
  12. Mtodos de instancia
    1. Object.prototype.__defineGetter__()
    2. __defineSetter__()
    3. __lookupGetter__()
    4. __lookupSetter__()
    5. Object.prototype.hasOwnProperty()
    6. Object.prototype.isPrototypeOf()
    7. Object.prototype.propertyIsEnumerable()
    8. Object.prototype.toLocaleString()
    9. Object.prototype.toString()
    10. Object.prototype.valueOf()
  13. Propiedades de instancia
    1. Object.prototype.__proto__
    2. Object.prototype.constructor
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