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Proxy.handler.deleteProperty

The handler.deleteProperty() method is a trap for the delete operator.

Syntax

var p = new Proxy(target, {
  deleteProperty: function(target, property) {
  }
});

Parameters

The following parameters are passed to the deleteProperty method. this is bound to the handler.

target
The target object.
property
The name or Symbol of the property to delete.

Return value

The deleteProperty method must return a Boolean indicating whether or not the property has been successfully deleted.

Description

The handler.deleteProperty() method is a trap for the delete operator.

Interceptions

This trap can intercept these operations:

Invariants

If the following invariants are violated, the proxy will throw a TypeError:

  • A property cannot be deleted, if it exists as a non-configurable own property of the target object.

Examples

The following code traps the delete operator.

var p = new Proxy({}, {
  deleteProperty: function(target, prop) {
    if (prop in target){
      delete target[prop]
      console.log('property removed: ' + prop)
      return true
    }
    else {
      console.log('property not found: ' + prop)
      return false
    }
  }
})

var result

p.a = 10
console.log('a' in p)  // true

result = delete p.a    // "property removed: a"
console.log(result)    // true
console.log('a' in p)  // false

result = delete p.a    // "property not found: a"
console.log(result)    // false

Specifications

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Basic support 49 12 18 No 36 10
Mobile
Android webview Chrome for Android Edge Mobile Firefox for Android Opera for Android iOS Safari Samsung Internet
Basic support 49 49 Yes 18 36 10 5.0
Server
Node.js
Basic support 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://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/deleteProperty