Proxy.revocable

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

Syntax

Proxy.revocable(target, handler);

Parameters

target

A target object (can be any sort of object, including a native array, a function or even another proxy) to wrap with Proxy.

handler

An object whose properties are functions which define the behavior of the proxy 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

Browser compatibility

See also

• Proxy