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Proxy.proxy.deleteProperty

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

Syntax

const 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

Trapping the delete operator

The following code traps the delete operator.

const 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
    }
  }
})

let 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
deleteProperty 49 12 18 No 36 10
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
deleteProperty 49 49 18 36 10 5.0
Server
Node.js
deleteProperty 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/Proxy/deleteProperty