Reflect.defineProperty()
The static Reflect
.defineProperty()
method is like Object.defineProperty()
but returns a Boolean
.
Syntax
Reflect.defineProperty(target, propertyKey, attributes)
Parameters
target
- The target object on which to define the property.
propertyKey
- The name of the property to be defined or modified.
attributes
- The attributes for the property being defined or modified.
Return value
A Boolean
indicating whether or not the property was successfully defined.
Exceptions
A TypeError
, if target
is not an Object
.
Description
The Reflect.defineProperty
method allows precise addition to or modification of a property on an object. For more details see the Object.defineProperty
which is similar. Object.defineProperty
returns the object or throws a TypeError
if the property has not been successfully defined. Reflect.defineProperty
, however, simply returns a Boolean
indicating whether or not the property was successfully defined.
Examples
Using Reflect.defineProperty()
var obj = {}; Reflect.defineProperty(obj, "x", {value: 7}); // true obj.x; // 7
Checking if property definition has been successful
With Object.defineProperty
, which returns an object if successful, or throws a TypeError
otherwise, you would use a try...catch
block to catch any error that occurred while defining a property. Because Reflect.defineProperty
returns a Boolean success status, you can just use an if...else
block here:
if (Reflect.defineProperty(target, property, attributes)) { // success } else { // failure }
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Reflect.defineProperty' in that specification. |
Standard | Initial definition. |
ECMAScript 2017 Draft (ECMA-262) The definition of 'Reflect.defineProperty' in that specification. |
Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | 49 | 42 (42) | No support | No support | No support |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | No support | No support | 42.0 (42) | No support | No support | No support |
See also
License
© 2016 Mozilla 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/reflect/defineproperty