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Proxy.revocable

The Proxy.revocable() method is used to create a revocable Proxy object.

Syntax

Proxy.revocable(target, handler);

Parameters

target
A target object to wrap with Proxy. It can be any sort of object, including a native array, a function, or even another proxy.
handler
An object whose properties are functions define the behavior of proxy p when an operation is performed on it.

Return value

A newly created revocable Proxy object is returned.

Description

A revocable Proxy is an object with following two properties {proxy: proxy, revoke: revoke}.

proxy
A Proxy object created with new Proxy(target, handler) call.
revoke
A function with no argument to invalidate (switch off) the proxy.

If the revoke() function gets called, the proxy becomes unusable: Any trap to a handler will throw a TypeError. Once a proxy is revoked, it will remain revoked and can be garbage collected. Calling revoke() again has no effect.

Examples

Using Proxy.revocable

var revocable = Proxy.revocable({}, {
  get: function(target, name) {
    return "[[" + name + "]]";
  }
});
var proxy = revocable.proxy;
console.log(proxy.foo); // "[[foo]]"

revocable.revoke();

console.log(proxy.foo); // TypeError is thrown
proxy.foo = 1           // TypeError again
delete proxy.foo;       // still TypeError
typeof proxy            // "object", typeof doesn't trigger any trap

Specifications

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
revocable 63 12 34 No 50 10
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
revocable 63 63 34 46 10 8.0
Server
Node.js
revocable 6.0.0

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://wiki.developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/revocable