Proxy() constructor

Baseline Widely available

This feature is well established and works across many devices and browser versions. Its been available across browsers since 2016 9.

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Proxy Proxy .

handler.apply(): .
handler.construct(): new .
handler.defineProperty(): Object.defineProperty .
handler.deleteProperty(): delete .
handler.get(): (get) .
handler.getOwnPropertyDescriptor(): Object.getOwnPropertyDescriptor .
handler.getPrototypeOf(): Object.getPrototypeOf .
handler.has(): in .
handler.isExtensible(): Object.isExtensible .
handler.ownKeys(): Object.getOwnPropertyNames Object.getOwnPropertySymbols
handler.preventExtensions(): Object.preventExtensions
handler.set(): (set) .
handler.setPrototypeOf(): Object.setPrototypeOf .

notProxied proxied . proxied .

const target = {
  notProxied: "original value",
  proxied: "original value",
};

const handler = {
  get(target, prop, receiver) {
    if (prop === "proxied") {
      return "replaced value";
    }
    return Reflect.get(...arguments);
  },
};

const proxy = new Proxy(target, handler);

console.log(proxy.notProxied); // "original value"
console.log(proxy.proxied); // "replaced value"

Specification
ECMAScript 2027 LanguageSpecification # sec-proxy-constructor

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This page was last modified on 2026 7 15 by MDN contributors.

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Proxy() constructor

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Handler

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