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

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

Specification
ECMAScript Latest Draft (ECMA-262)
The definition of 'Proxy Revocation Functions' in that specification.

Browser compatibility

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
revocableChrome Full support 63Edge Full support 12Firefox Full support 34IE No support NoOpera Full support 50Safari Full support 10WebView Android Full support 63Chrome Android Full support 63Firefox Android Full support 34Opera Android Full support 46Safari iOS Full support 10Samsung Internet Android Full support 8.0nodejs Full support 6.0.0

Legend

Full support  
Full support
No support  
No support

See also