← 返回首页
WeakMap.prototype.has() - JavaScript | MDN
HTML

HTML: Markup language

HTML reference HTML guides Markup languages
CSS

CSS: Styling language

CSS reference CSS guides Layout cookbook
JavaScriptJS

JavaScript: Scripting language

JS reference JS guides
Web APIs

Web APIs: Programming interfaces

Web API reference Web API guides
All

All web technology

Technologies Topics
Learn

Learn web development

Frontend developer course Learn HTML Learn CSS Learn JavaScript
Tools

Discover our tools

About

Get to know MDN better

Blog
Toggle sidebar
  1. 개발자를 위한 웹 기술
  2. JavaScript
  3. JavaScript 참고서
  4. 표준 내장 객체
  5. WeakMap
  6. WeakMap.prototype.has()
Theme
  • OS default
  • Light
  • Dark
한국어
Remember language Learn more

This page was translated from English by the community. Learn more and join the MDN Web Docs community.

View in English Always switch to English

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 2015년 7월.

has() 메서드는 지정된 키를 가진 요소가 WeakMap 객체에 존재하는지를 나타내는 불리언 값을 반환합니다.

In this article

시도해 보기

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

구문

js
has(key);

매개변수

key

필수로 요구되며, WeakMap 객체에서 존재 여부를 테스트할 요소의 키입니다.

반환 값

불리언

WeakMap 객체에 지정된 키를 가진 요소가 있으면 true를 반환하고, 그렇지 않으면 false를 반환합니다.

예제

has 메서드 사용하기

js
const wm = new WeakMap(); wm.set(window, "foo"); wm.has(window); // true 반환 wm.has("baz"); // false 반환

명세서

Specification
ECMAScript® 2027 Language Specification
# sec-weakmap.prototype.has

브라우저 호환성

Enable JavaScript to view this browser compatibility table.

같이 보기

Help improve MDN

Was this page helpful to you?
Yes No
Learn how to contribute

This page was last modified on 2025년 2월 11일 by MDN contributors.

View this page on GitHub • Report a problem with this content
  1. 표준 내장 객체
  2. WeakMap
  3. 생성자
    1. WeakMap() constructor
  4. 인스턴스 메서드
    1. WeakMap.prototype.delete()
    2. WeakMap.prototype.get()
    3. getOrInsert()
    4. getOrInsertComputed()
    5. WeakMap.prototype.has()
    6. WeakMap.prototype.set()
  5. 상속
  6. Object/Function
  7. 정적 메서드
    1. Function.prototype.apply()
    2. Function.prototype.bind()
    3. Function.prototype.call()
    4. Function.prototype.toSource()
    5. Function.prototype[@@hasInstance]()
  8. 정적 속성
    1. Function: displayName
    2. Function.prototype.length
    3. Function: name
    4. Function
    5. Function.arguments
    6. Function.prototype.caller
  9. 인스턴스 메서드
    1. Object.prototype.__defineGetter__()
    2. Object.prototype.__defineSetter__()
    3. Object.prototype.__lookupGetter__()
    4. Object.prototype.__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()
  10. 인스턴스 속성
    1. Object.prototype.__proto__
    2. Object.prototype.constructor

Your blueprint for a better internet.

MDN Contribute Developers

Visit Mozilla Corporation’s not-for-profit parent, the Mozilla Foundation.
Portions of this content are ©1998–2026 by individual mozilla.org contributors. Content available under a Creative Commons license.