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Reflect.getOwnPropertyDescriptor

The static Reflect.getOwnPropertyDescriptor() method is similar to Object.getOwnPropertyDescriptor(). It returns a property descriptor of the given property if it exists on the object, undefined otherwise.

Syntax

Reflect.getOwnPropertyDescriptor(target, propertyKey)

Parameters

target
The target object in which to look for the property.
propertyKey
The name of the property to get an own property descriptor for.

Return value

A property descriptor object if the property exists in target object; otherwise, undefined.

Exceptions

A TypeError, if target is not an Object.

Description

The Reflect.getOwnPropertyDescriptor method returns a property descriptor of the given property if it exists in the target object, undefined otherwise. The only difference to Object.getOwnPropertyDescriptor() is how non-object targets are handled.

Examples

Using Reflect.getOwnPropertyDescriptor()

Reflect.getOwnPropertyDescriptor({x: 'hello'}, 'x')
// {value: "hello", writable: true, enumerable: true, configurable: true}

Reflect.getOwnPropertyDescriptor({x: 'hello'}, 'y')
// undefined

Reflect.getOwnPropertyDescriptor([], 'length')
// {value: 0, writable: true, enumerable: false, configurable: false}

Difference to Object.getOwnPropertyDescriptor()

If the target argument to this method is not an object (a primitive), then it will cause a TypeError. With Object.getOwnPropertyDescriptor, a non-object first argument will be coerced to an object at first.

Reflect.getOwnPropertyDescriptor('foo', 0)
// TypeError: "foo" is not non-null object

Object.getOwnPropertyDescriptor('foo', 0)
// { value: "f", writable: false, enumerable: true, configurable: false }

Specifications

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
getOwnPropertyDescriptor 49 12 42 No 36 10
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
getOwnPropertyDescriptor 49 49 42 36 10 5.0
Server
Node.js
getOwnPropertyDescriptor 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/Reflect/getOwnPropertyDescriptor